D.A. Jackie Lacey offers immunity in exchange for witness testimony in Ed Buck investigation

LOS ANGELES (FOX 11) - In a sit-down interview with FOX 11 Monday evening, Los Angeles County District Attorney Jackie Lacey responded to outside criticism regarding the Ed Buck investigation.

"We can't file a criminal case based on who has the loudest voice," Lacey said. "I may feel that a person is guilty, but my job as a prosecutor is always to look for the evidence."

Democratic donor Ed Buck is currently under investigation by the West Hollywood Sheriff's Department as detectives probe the suspicious deaths of two gay black men inside of his apartment a year and a half apart.

Related: FOX 11 confronts Democratic donor Ed Buck amidst investigation into 2 deaths at his apartment

"Obviously, the odds of two people dying has to be more than a coincidence, but once again we really need that evidence," Lacey said.

In July 2017, Gemmel Moore was found dead inside of Buck's apartment on Laurel Avenue.

The coroner determined his death was the result of an accidental meth overdose.

Moore has written in his journal that Buck had given him his first injection of crystal meth, it hurt, and he was becoming addicted to the pain.

Related: Mom of man who died in WeHo home of Democratic donor Ed Buck files lawsuit

Prosecutors declined to charge Buck in the case.

In January of this year, Timothy Dean also died inside of Buck's apartment. His cause of death has not yet been released.

"We immediately reopened the first case, cause with the second body coming out of there, and the similarities between the two deaths and the two men's relationship to Mr. Buck, we decided to take a look at the first case as well as the second case," Lacey said.

Lacey told FOX 11 that right now, detectives just don't have the evidence to prove that Buck was responsible for either death.

"That's the piece that we're missing is proving who injected who," Lacey said. "Because obviously if the victim has injected themselves with drugs then Buck would not be guilty of anything."

That's why Lacey said, detectives need potential witnesses to come forward.

"We don't care about drug use or anything like that, we're willing to grant them immunity but we really need to hear from witnesses," Lacey said.

When asked how to respond to critics who believe Buck is being treated with kiddy gloves because of his connections, Lacey replied, "It simply is the circumstances, if the first victim and the second victim had died from gunshot wounds, of course, that's not something that's natural so the sheriff's department would have immediately arrested him, but in this case because it was an overdose by men who had a history of drug abuse, we have to look more closely."

Despite prosecutors efforts, activists are not happy with the progress of the case. They delivered 30,000 signatures to Lacey's office to call for Bucks prosecution.

Lacey said she hears their frustration but needs evidence to support the accusations against Buck.

"If we go out there and arrest him now, the clock starts ticking, and it wouldn't be ethical right now to arrest him until we really had the evidence," she added.

Lacey said Buck has no connection to her office and that she has never met him. She also said he donated $100 to her campaign in 2012, but she said she returned that money after the death of Gemmel Moore.

FOX 11 reached out to Buck for a comment, he told us, "I don't want to talk to you."