An investigation was launched in November after Christoper Lucia, 35, was taken to a hospital after testing positive for fentanyl. While under their care, he failed to regain consciousness and died after several days on Nov. 13.

"Over the course of their investigation, detectives identified two people suspected of supplying the fentanyl to Christopher, as well as the person suspected of being their source of fentanyl," said Riverside Police Department in a statement.

Investigators have served several search warrants over recent weeks, including one in the 5500 block of Inner Circle Drive and the 4900 block of Gardena Drive in Riverside, as well as another in the 7220 block of Font Avenue in Jurupa Valley.

During those searches, they located and seized nearly a pound of powdered fentanyl, as well as evidence that the suspects had continued to sell the highly potent synthetic opioid even after Lucia's death. They also seized 11 firearms during the investigation.

Riverside residents Jaclyn Sherman, 30, and Miguel Garcia, 37, were both arrested and booked for Lucia's murder, police said. Sherman was also charged with the possession of illegal narcotics for the purposes of sales.

Both are being held in custody on $1 million bail.

Additionally, Jurupa Valley man David Ray Mullins, 46, is also in custody for illegal narcotics and weapons violations. He is expected to be charged with murder.

A fourth person, who remains unidentified, was arrested and booked for possession of fentanyl as well, police noted.

"The death toll from fentanyl overdoses in Riverside County continues to rise and put all our community members at risk," said RPD Chief Larry Gonzalez. "We won't stop fighting to get rid of this deadly poison from our neighborhoods."

Riverside County District Attorney Mike Hestrin doubled down on the sentiment.

"Along with our law enforcement partners, our office will continue to fight the fentanyl epidemic for the safety of our community. Those who provide fentanyl causing the death of another in Riverside County should expect to be prosecuted for homicide and be held fully accountable for the life they took with this deadly poison," he said.

Police say that the investigation is ongoing and that there is no further information to provide at the time.

Anyone who may know more is asked to contact detectives at (951) 353-7216.