Walterhouse confessed to providing the woman information about covert prostitution operations to "keep her out of jail" after his arrest late Wednesday night, according to the charging documents.
At a Thursday afternoon press conference, police and city officials said systemic changes put in place since a major sexual misconduct scandal hit the department this summer are working. Oakland Mayor Libby Schaaf and OPD Deputy Chief John Lois lauded an unnamed officer for reporting the alleged crimes, which spawned an investigation.
"The reaction from every level of the organization has been one of anger and disappointment," Lois said. "I want to make it clear that criminal misconduct will not be tolerated at the Oakland Police Department. Therefore I think it warrants repeating that an Oakland police officer came forward and initially reported this misconduct."
Schaaf said she "recognizes that the public has got to find these allegations very disturbing."
That Walterhouse continued an inappropriate relationship with a woman working in the sex trade -- even after the sexual misconduct scandal involving the teenage daughter of an OPD dispatcher toppled a succession of three police chiefs and led to criminal charges for three current and former city police officers -- is "completely outrageous," Schaaf said.
"It is incredibly disturbing that in light of what happened this summer, any officer could think that it was at all acceptable to engage in this type of behavior and further sully the reputation of this department," she said.
Original post, 1:39 p.m. Thursday: An Oakland police officer was arrested Wednesday under suspicion of obstruction of justice counts and a misdemeanor prostitution offense, according to a statement from the Police Department.
Officer Ryan Walterhouse, 26, was arrested in the past 24 hours and released after paying bail, according to Alameda County jail records.
The arrest is unrelated to a sprawling sexual misconduct case involving dozens of Bay Area law enforcement officers from multiple agencies and the teenage daughter of an OPD dispatcher, according to the Police Department.
But the latest allegations follow a similar pattern: A relatively new officer assigned to a hot spot for human trafficking is accused of trading protected law enforcement information for sex. From the East Bay Express:
Multiple sources close to the police department said Walterhouse is being investigated for obstruction of justice and a prostitution-related offenses.
Walterhouse allegedly slept with a sex worker, and then traded confidential law enforcement information about police vice operations to see the sex worker again.
"The Oakland Police Department takes all allegations of misconduct involving our employees seriously," OPD spokeswoman and Officer Johnna Watson wrote in a statement. The commander of OPD's criminal investigations division participated in the arrest, according to Watson.
Ryan Louis Walterhouse was an OPD trainee for part of 2014, according to state salary data from Transparent California. The database indicates he became a sworn Oakland police officer in 2014 and continued in the position through 2015.
"[T]he arrest of the officer last evening is not connected to the sexual misconduct case involving Oakland police officers and Celeste Guap," Watson wrote.
Three current and former Oakland officers have been criminally charged in that case -- involving now 19-year-old Jasmine Abuslin, who is also known as Celeste Guap.
Officer Brian Bunton faces a felony conspiracy to obstruct justice charge for allegedly tipping off Abuslin to a prostitution sting in exchange for sex. He's also charged with a misdemeanor for engaging in prostitution.
Officer Giovani LoVerde faces a single felony charge for alleged oral copulation with a minor -- allegedly with Abuslin before she turned 18 last August. Retired Sgt. Leroy Johnson faces a misdemeanor for failing to report child abuse or neglect.
Reportedly a family friend, Johnson allegedly agreed not to tell anyone when Abuslin confided that she had sex with other OPD officers, some while she was underage, according to charging documents.
Alameda County District Attorney Nancy O'Malley announced in early September her intention to charge a total of seven current and former peace officers related to the scandal that also saw the resignation of three police chiefs over about a week in June.
Former Contra Costa Sheriff's Deputy Ricardo Perez was charged with felony oral copulation with a minor and two misdemeanor counts of engaging in lewd conduct in a public place, and prosecutors charged former Livermore Officer Daniel Black with five misdemeanor counts for engaging in prostitution, lewd conduct in a public place and providing alcohol to a minor.
OPD Officer Warit Utappa and former Officer Tyrell Smith were expected to face misdemeanor charges for illegally accessing protected law enforcement data, O'Malley said in September, but they have yet to be formally charged.