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.