Each of them remains in custody on $250,000 bail, said Michael O'Connor, an assistant district attorney at the Alameda County District Attorney's Office.
During Wednesday's hearings, Palmon and Morton asked for a bail reduction but the court denied their requests. All four are scheduled to enter pleas on Dec. 1.
For the first time since the dam was vandalized, authorities have released extensive details about what they believe happened in the early hours of May 21 when the dam, overseen by the Alameda County Water District, was damaged. That includes statements that three of the suspects gave to police and a report that involved one of the men calling a police tip line from his jail cell, implicating one of the other suspects.
Fremont police first received word of a security breach in the area when the department got a call from Bay Alarm that one of the company's alarms on water district property near Rancho Arroyo Park had gone off. The security firm said its employees had seen several young males running away.
When police showed up they didn't find any evidence of vandalism. But the following afternoon the water district's security manager contacted police to report that the dam had been cut.
Two months later, Fremont police sent out a press release containing video images of what were believed to be the suspects.
In the weeks after that release was published, two people contacted Fremont police to say they'd heard that Palmon and Elkhouri were behind the vandalism.
Police then obtained search warrants for two men's cellphone data, revealing that they had been near the area of Alameda Creek where the vandalism took place at around the same time the crime occurred. That morning Palmon had several phone conversations with Jeffery, police said.
Last Friday, Morton was arrested on an unrelated narcotics warrant.
"While placing Morton under arrest he spontaneously stated something to the effect of 'you all think i did the dam thing,'" police wrote in charging documents.
In an interview with police, the documents say, Morton said he and the other three suspects were drunk and stoned when they walked to the area and started jumping on the dam because "they thought it felt like a trampoline."
The day after Morton was arrested, police arrested Jeffery, Palmon, and Elkhouri.
Last Sunday, authorities say Palmon called the Fremont Police Department's crime tip line from his cellphone while inside his jail cell, implicating Elkhouri as the person who actually slashed the dam.
The following day, Palmon and Jeffrey told police in interviews that Elkhouri cut the dam multiple times, authorities said.
Elkhouri revealed no information about the incident after asking for a lawyer, the charging documents say.
One of the men is represented by the Alameda County Public Defender's Office, which did not return calls seeking comment.
Meantime, the arrests have led to relief at the water district.
"We are pleased that the Fremont Police Department has dedicated the resources for the six-month-long investigation," said Sharene Gonzales, the water agency's spokeswoman.
The development in the case comes a couple of weeks after the replacement dam built over the last several months became operational.
"With the rain that we're hoping to receive, we will be able to divert that water and recharge our local groundwater basin for drinking water for our customers," Gonzales said in an interview.
In June, the EPA told KQED it had launched an investigation into the vandalism because it may have been a violation of the federal Safe Drinking Water Act.