Ed Buck, a Democratic donor arrested this week in Los Angeles who allegedly preyed on vulnerable, younger black men, had multiple victims he injected with methamphetamine, earning the nickname "Doctor Kevorkian" with some, federal investigators said.

Buck, who faces a federal charge of distribution of methamphetamine resulting in death, exploited at least 10 men, offering them drugs, sex and money, prosecutors said in a court filing Thursday.

Gemmel Moore, 26, and Timothy Dean, 55, fatally overdosed inside Buck's West Hollywood apartment. Buck faced no charges initially.

Buck was arrested Tuesday and charged with multiple felonies in connection with an incident during which he "nearly killed a third victim," the Los Angeles District Attorney's Office said.

Ed Buck arrested:Democratic donor charged with running 'drug den' after another man overdosed in Los Angeles home

Buck is a “serious threat to public safety" who preyed on homeless and vulnerable men, U.S. Attorney Nick Hanna said. Los Angeles prosecutors described Buck as "a violent, dangerous sexual predator."

Buck's attorney, Seymour Amster, did not respond to USA TODAY's requests for comment this week. Buck remained in custody after appearing in Los Angeles Superior Court and federal court Thursday. He did not enter into a plea, and the federal judge set a detention hearing for Thursday.

If convicted of the federal charge, he could face a mandatory minimum sentence of 20 years in federal prison to a maximum sentence of life without parole.

Buck, a former West Hollywood City Council candidate and well-known political activist in LGBTQ circles in Los Angeles, has donated thousands of dollars over the years to Democratic candidates and causes.

In the federal criminal complaint, investigators said, Buck provided methamphetamine that directly resulted in Moore's death in 2017 and described multiple other incidents at his apartment, including Dean's death this year.

Watch:Democratic donor charged in drug overdose deaths

Moore and Buck texted after the younger man moved back home to Texas. Buck told him to "be here now," the complaint says.

Moore told his mother and aunt that Buck would shoot him up with drugs, the court papers say. Buck allegedly purchased an airline ticket and arranged a ride for Moore to arrive at his apartment.

When ambulances arrived at the apartment July 27, 2017, Moore was on a mattress and not breathing, wearing only socks. An autopsy report determined he died from a methamphetamine overdose, and deputies noted puncture marks on his arm.

On Jan. 7, deputies responded to a similar scene, described in the complaint: Dean (though he is not named in the court papers) was unresponsive and nearly naked on Buck's floor. He fatally overdosed, a coroner's report determined.

In both cases, Buck denied any wrongdoing to deputies, saying the men were close friends.

Interviews with other men who said they were victims of Buck described how he would pay for male prostitutes and often injected the men with drugs against their will, the complaint says.

Buck was referred to as "Doctor Kevorkian," a reference to Jack Kevorkian who went to prison for his role in assisting patients' deaths, and "was well known for compensating male prostitutes with drugs and money," a victim told investigators, according to the complaint.

One victim told investigators that when Buck asked to inject him with methamphetamine, he was apprehensive because he had never done the drug, the complaint says. He agreed to a small dose, then Buck allegedly "emptied an entire syringe in him."

Contributing: The Associated Press. Follow USA TODAY's Ryan Miller on Twitter @RyanW_Miller