When Babette Papineau enrolled at College of Marin in the spring of 2023, she hoped to become a naturalist.

The 34-year-old mother of two took an environmental science class with professor Joe Mueller and quickly came to see him as an environmental hero and an expert in the field she hoped to enter.

“I put him on a pedestal,” Papineau said.

In the summer of 2024, Papineau said she reached out to Mueller for guidance after deciding to pursue the college’s natural history certificate.

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Papineau and Mueller formed a professional and later, romantic relationship. They dated on and off until last summer, when Papineau filed a Title IX complaint against Mueller, alleging that he coerced her into a relationship and engaged in unwanted and inappropriate sexual conduct with her while she was his student and relied on him for mentorship.

Papineau’s complaint is one of several accounts that reveal a broader pattern in the college’s natural history program. Interviews with multiple current and former College of Marin students, along with Title IX investigative records reviewed by KQED, describe what former students said was a decadeslong pattern in which Mueller blurred professional boundaries with students, played favorites in class and intimidated students he disliked.

Students said Mueller used mentorship, favoritism and control over required coursework in ways that altered their education, shaped their career decisions and created fear inside the department.[aside postID=news_12086091 hero='https://cdn.kqed.org/wp-content/uploads/sites/10/2026/06/CA-Teacher-Discipline-Holly.jpg']College of Marin commissioned workplace investigation law firm Van Dermyden Makus to conduct a third-party evidentiary review of Papineau’s complaint. After a closed-door hearing in May, a third-party consultant found sufficient evidence to support multiple violations of the school’s sexual harassment policy and one violation of its sexual assault policy, according to documents reviewed by KQED.

Mueller was placed on immediate leave on Thursday, according to a summary of remedies from the district. It said it planned to “initiate” his termination.

According to the findings report, which was delivered to the school’s Title IX coordinator June 29, Mueller was previously found in violation of college harassment policies on two prior occasions since 2016.

In one case, the school found that Mueller “exercised extremely poor judgement and unprofessional conduct and placed the District at risk of serious liability by engaging in sexual relationships with students … and taking students to a store with sexually-based items” during an overnight field trip.

According to the findings report, which was delivered to the school’s Title IX coordinator on June 29 and reviewed by KQED, investigators found that the college had previously found Mueller to have violated its harassment policies on two prior occasions since 2016.

Mueller initially declined to comment on the details of the investigation but later provided a written statement disputing many of the allegations.

Following multiple requests to Mueller for comment, several current and former students contacted KQED to express support for the professor and describe positive experiences with him as an instructor and mentor.

Mentorship and power

Mueller told investigators that he noticed Papineau’s talent as a writer in his spring 2023 course and later invited her and several classmates to give a presentation on the environmental impact of grass lawns.

The two remained in touch through email, discussing environmental issues and Papineau’s move to Fairfax, the small North Bay town where Mueller lived. Mueller later told investigators their friendship developed in summer 2024.

Papineau said she initially viewed Mueller as a mentor. She began working on a website for the natural history program at his request and later spoke on his behalf at a local Board of Supervisors meeting. The two also began hiking together and communicating more frequently.

College of Marin in Kentfield on May 22, 2026. (Tâm Vũ/KQED)

“I was very excited thinking, ‘Wow, this professor who was such an inspiration to me seems to be offering me mentorship, which was like a dream come true,’” Papineau told KQED.

Papineau said the relationship became romantic during a hike in summer 2024 when Mueller kissed her. She said the relationship was consensual at first.

“I was a little conflicted about it because I was like, ‘He is my hero, and so if he wants something more, I have to at least give that a try,’” Papineau said.

The relationship changed after class resumed in fall 2024, Papineau said.

She enrolled in Mueller’s ecology class, the first of several classes she would take from him while they were romantically involved. At the time, College of Marin discouraged, but did not prohibit, relationships between instructors and students.[aside postID=news_12087201 hero='https://cdn.kqed.org/wp-content/uploads/sites/10/2026/06/CollegeGraduationGetty.jpg']In November 2025, the Marin Community College District revised its harassment policy to prohibit most relationships between students and employees.

“Such relationships present an inherent imbalance of power and carry a significant risk of exploitation, compromising the integrity of the educational environment,” the policy states.

The college did not respond to questions about what prompted the change. Spokesperson Nicole Cruz said it was campus policy not to comment on specific student or employment matters.

“College of Marin is committed to providing an academic and work environment free of unlawful discrimination on the basis of sex, including sexual harassment under Title IX,” she said via email. “College of Marin has a robust and thorough process for investigating complaints of unlawful discrimination … Further, College of Marin strictly prohibits retaliation.”

Mueller told investigators that Papineau initiated most of their contact and frequently shared details about her personal life. At one point, he said she told him she’d broken up with her boyfriend and moved out of his residence, according to the investigators’ report.

In a statement, Mueller said: “In my 35 years of teaching, I have never, not once, asked a woman out on a date or accepted an invitation to go out on a date that was currently enrolled in one of my classes.” He said in two instances, in 2024 and 1998, women that he “was in well-established relationships with” wanted to take his classes and he could not prohibit them from enrolling.

Papineau was first Mueller’s student in the spring of 2023 and told Mueller in May 2024, before they began dating, that she planned to take his course that fall, according to emails viewed by KQED.

A pattern of favoritism

Before Papineau filed her complaint, other students said they had already come to view Mueller as a professor who rewarded favored students and marginalized others.

Lily Wales enrolled in Mueller’s environmental science course in fall 2024 during their first semester at College of Marin.

Mueller was “sort of legendary” on campus, according to Wales. But he was also known for being harsh with students, while singling out some — including Wales — as favorites.

“He would pull me aside after class and tell me how good I was doing and say that he had a lot of connections in the biology world,” Wales said.

College of Marin biology professor Joe Mueller on a ridge overlooking Home Bay, part of Drake’s Estero on Jan. 10, 2024. (Cy Musiker/KQED)

Wales, who was 17 at the time, said Mueller complimented them, offered networking opportunities and invited them on hikes, which they declined.

At first, Wales said the attention was validating.

“I was pretty young, and so I was really naive,” Wales said. “I was like, ‘It’s so great that so early on there’s somebody in the field that really wants to help me.’”

Around midterms, however, they became uncomfortable with the attention.

When students were working on group projects, Wales said Mueller critiqued other groups while praising theirs without closely examining the work. Wales said they didn’t study well for the midterm exam and answered multiple questions incorrectly, but were awarded a perfect score.

“That was a moment where I was like, ‘I feel like there’s something going on and I don’t want it to get to a point of there being a relationship that’s being formed,’” they said.

Shortly after, Wales said they stopped attending Mueller’s class and had avoided taking any of his others throughout their time at College of Marin. Mueller reached out to Wales to express his concern after they had missed a few weeks of class, according to an email viewed by KQED.

The cost of staying in good standing

Walker Newell took about five classes with Mueller during his first few years at College of Marin. He alleges that the professor gave preferential treatment to young, pretty women, while treating others harshly.

“There’s definitely people who get weeded out of the classroom that essentially [are] people that Joe doesn’t want in the classroom,” Newell told KQED.

Newell recalled that Mueller would often pause mid-lecture to make comments about a student who had an accommodation allowing them to take notes on a laptop. According to Newell, Mueller suggested that the student’s typing distracted classmates and slowed the class.

College of Marin in Kentfield on May 22, 2026. (Tâm Vũ/KQED)

Another former student and college employee, who requested anonymity out of fear of retaliation, similarly said Mueller was often uncooperative with accommodations and singled students out in class.

Mueller said that he tries to discourage students from typing notes and asks those who do to speak with him about the benefits of handwriting.

“I don’t disparage them; somebody might take it that way,” Mueller said.

Mueller described himself as a dedicated teacher and said he would never intentionally treat students unfairly.

Newell said Mueller liked to be seen as “all-knowing” and “grand.”

Initially, Newell said, he benefited from Mueller’s favor, and it felt good to be praised.

“When you’re on his side, it’s great. You get questions wrong on a test, and they get marked right,” Newell said. “But then, after a while, you just can’t see that happen to other people and just feel OK.”[aside postID=news_12084071 hero='https://cdn.kqed.org/wp-content/uploads/sites/10/2026/05/260518-SCU_Sutter-med-school-02-KQED.jpg']That dynamic, Newell said, created an environment in which students understood there were advantages to remaining in Mueller’s good graces.

Newell also described an incident during a two-week field course along the West Coast in 2022. According to Newell, Mueller offered to waive the cost of the trip if he helped transport equipment and assist with camp setup and breakdown.

When they returned, though, Newell alleges that Mueller charged him hundreds of dollars, saying that he owed him for the cost of the trip, minus a small hourly wage for his work.

Mueller said in an email that Newell had been unable to complete the work he promised to do, that the two reached a compromise and that Mueller paid half of the cost.

“He got a damn good deal because I cared,” Mueller said.

Newell said Mueller repeatedly singled out a middle-aged female student during the trip. After several students stopped at a coffee shop without permission, Newell said Mueller focused his criticism on the woman and berated her.

“She was bawling, and she was like, ‘I’m leaving,’” Newell said. “It was just hard to see a grown woman just full on crying and sobbing.”

Someone later reported Mueller’s conduct on the trip, and Newell said he was interviewed as part of an investigation. It remains unclear what conclusions the college reached or whether Mueller faced disciplinary action. College of Marin did not respond to questions about the investigation.

When the relationship changed

Between spring of 2024 and summer 2025, Papineau and Mueller exchanged dozens of emails reviewed by KQED.

Papineau wrote about kissing and being with Mueller, and said she had dreams of them marrying and living together with her daughters.

Papineau also expressed concerns about Mueller’s reactions to her interactions with male classmates and said she felt pressured to manage his emotions. She said that during his fall ecology class, she sat near the edge of the room and focused her attention almost exclusively on him because she worried about upsetting him.

Babette Papineau stands for a portrait in her home in Fairfax, California, on Wednesday, May 27, 2026. Papineau is a student at the College of Marin and filed a Title IX complaint against her professor, Joe Mueller, after she said he coerced her into a relationship. (Juliana Yamada for KQED)

After she said she had learned that Mueller previously dated former students, Papineau wrote to him in an email that she “felt almost like I was an insect caught in [his] web.”

In another email, Mueller acknowledged previous relationships with former students.

“[W]hen I was first teaching, I didn’t realize how dating former students could lead to problems,” he wrote. “It was certainly not of a predatory nature, as back then I was very shy and only dated women that pursued me.”

Papineau said she threatened to end their relationship in fall 2024. She alleges that Mueller warned that doing so would jeopardize her future in the natural history program. Mueller teaches several courses required for the natural history certificate, including some that other instructors do not offer.

“The story became: ‘Think about your future, think about your career. If we are not together, you cannot carry on in this department,’” Papineau said.[aside postID=news_12084624 hero='https://cdn.kqed.org/wp-content/uploads/sites/10/2026/05/Screenshot-2026-05-21-at-10.21.25%E2%80%AFAM.jpeg']“Education, for me, it’s given me purpose. So the threat of that being taken away was absolutely not something I was OK with. And so I stayed in that with Joe [Mueller],” she said.

In emails, Mueller expressed frustration about the couple’s lack of physical intimacy and questioned whether Papineau’s feelings for him were fading. Papineau said that after she told Mueller she didn’t want to be intimate because of past trauma, he paid for therapy and expected updates about her sessions and whether she felt closer to being comfortable having sex with him.

He also sent what he called “everlasting love assignments” — quiz-style questionnaires about their relationship.

“If you could travel anywhere in the world with me, where would you go? What would we do? … Remember, due to the nature of the exercise, you must include love in at least one answer,” one of the quizzes stated.

“When we were together in physical presence, you could tell that I wasn’t comfortable,” Papineau said. “So part of my job was to make up for that in writing.”

Papineau said she became increasingly dependent on Mueller. He paid her for work on the book project and contributed more than $11,000 toward her rent, according to copies of checks reviewed by KQED. He also paid more than $2,000 toward therapy expenses, according to images of transaction records reviewed by KQED.

The two continued dating until spring 2025. Even after they broke up, they remained in contact and continued collaborating on a book project.

Papineau said she ultimately filed her Title IX complaint after learning that other students had similar experiences. What she initially viewed as mentorship had become the foundation of a complaint that raised broader questions about power, favoritism and influence within the college’s natural history program.

Students who walked away

In March 2025, Papineau confided in another professor in the geology department, who later confirmed the conversation to Title IX investigators.

According to the investigative report, the professor, who co-taught multiple classes with Mueller, said other students had raised concerns about Mueller’s fairness. The professor also recalled a female student asking in 2017 whether anyone else taught one of Mueller’s classes because she wanted to avoid taking a course with him.

For some students, avoiding Mueller was difficult.

A directional sign at College of Marin in Kentfield on May 22, 2026. (Tâm Vũ/KQED)

“The difficult thing for a lot of students is that [Mueller] is the only teacher that teaches [environmental science] and, I think, three of his other classes,” Wales said. “If you need any of the classes that he teaches, there’s no other option.”

When Wales stopped attending Mueller’s class in fall 2024, they allege that they received an F that temporarily placed them on academic probation. They later petitioned to have the grade removed from their record. Wales said the four-year university they hope to transfer to does not require Mueller’s course — a factor in their decision to apply there.

Newell also altered his plans.

Instead of pursuing College of Marin’s natural history certificate, which required additional classes taught only by Mueller, he switched to biology.

Papineau changed her major to philosophy and said she no longer believed a future in natural history was feasible.

Taken together, the students described a program in which one professor’s influence extended beyond the classroom and shaped decisions about majors, certificates, careers and whether students remained in the field at all.

“I did meet people frequently who were like, ‘Be careful around Joe,’” Papineau said. “But I didn’t believe that for a long time until I saw it for myself.”

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