SANTA ANA (AP) — An Orange County court on Tuesday began hearing evidence on allegations that authorities used jailhouse informants in high-profile murder and gang-crime cases in violation of the suspects’ constitutional rights.

Assistant public defender Scott Sanders alleges that authorities used the informants to improperly interrogate suspects and tried to hide what they did in a host of cases, including the prosecution of mass-murder suspect Scott Dekraai.

Sanders is asking Judge Thomas M. Goethals to strike the death penalty for Dekraai, who is charged with killing eight people in a rampage at a Seal Beach hair salon in 2011, and recuse the district attorney’s office from the case. Prosecutors say the allegations are unfounded.

The hearing — expected to last several weeks and include testimony from informants and prosecutors — is highly unusual and has created a buzz among defense attorneys in this suburban California county who are now questioning whether their own clients may have been improperly approached by jailhouse informants.

Former gang member Fernando Perez testified that the authorities who oversaw his informant activities in the jail told him not to actively question inmates. But Perez said authorities told him that if inmates confessed to him, he could write down what they said.

“I wasn’t trying to work anybody,” said Perez, who is facing a potential life sentence for his own crimes and was a leader in the Mexican Mafia. “People like to brag about their cases. People like to brag about their crime or whatever. In the gang world, they call it war stories.”

Sanders accuses authorities of intentionally shuffling inmate informants throughout the jails to get them to obtain statements from high-profile suspects. He argues that it was not a coincidence that Dekraai was housed next to Perez, who had been seeking to curry favor with prosecutors to try to avoid a life sentence. Nor was it a coincidence that Perez befriended Dekraai to get him to talk, Sanders said.

Prosecutors said the allegations are unfounded and assert they initially did not turn over evidence related to the informant because they did not plan to call him as a witness. Rather, after learning that Dekraai was talking about the crime, prosecutors decided to bug Dekraai’s cell and now want to use the conversations recorded between the two men as evidence at his trial.

Assistant District Attorney Dan Wagner wrote in court papers that he believes the recordings can be used because it does not appear that the informant elicited information from Dekraai.

Jailhouse informants can offer up information to authorities, but they are not allowed to actively question suspects who have lawyers or who have requested legal representation.

Sanders also questioned Perez — who acknowledged after receiving immunity that he had lied on the stand at his own trial and helped compile a list of targets the Mexican Mafia wanted dead before he turned a corner and started collaborating with law enforcement — about his conversations with double-murder suspect Daniel Wozniak.

Perez said Wozniak confessed to him that he had chopped up his victim and severed his head after Perez asked him “what was he busted for.”

“If they felt comfortable with me, I don’t know what it was about me or what, but they confessed what they did,” he said.