Mark (left) and Scott Ruffalo
Scott Ruffalo had "very slight" traces of cocaine, morphine and alcohol in his system at the time of his death, L.A. County Coroner spokesman Ed Winter confirms to PEOPLE.
"Ruffalo's toxicology results showed a very slight trace of cocaine and alcohol," Winter says. "He also had slight traces of morphine which could've been due to prescription medication.
"All we can conclude from this is that he was not under the influence of drugs when he was shot due to the small amount," says Winter, who adds that coroners still maintain Ruffalo's death was a homicide.
Ruffalo, 39, the younger brother of actor Mark Ruffalo, was found shot in the head
Dec. 1 at his Beverly Hills condominium and died a week later.
Days after the shooting, Shaha Mishaal Adham, 26, turned herself in to police in connection with the case. She was arrested but later released after her lawyer, Ronald Richards, said he provided evidence that Ruffalo had died from playing Russian roulette.
Richards also claimed that Ruffalo "is a known cocaine user who would use drugs often and play with guns in front of several witnesses."
Court documents show that Ruffalo had a checkered past: In early 2002, he pleaded guilty to drug possession with an intent to sell. He struck a plea deal and was sentenced to three years probation and two days in jail.
Beverly Hills police are still investigating this case, and no new arrests have been made.