Garrison, 26, who co-starred in Fox television's "Prison Break," was behind the wheel of a 2001 Land Rover on Dec. 2 when it plowed into a tree on South Beverly Drive near Olympic Boulevard.
With their investigation finished, Beverly Hills police announced that they were sending a recommendation to the Los Angeles County district attorney's office that Garrison be charged with two felonies: gross vehicular manslaughter and driving under the influence. They also recommended a misdemeanor charge of contributing to the delinquency of a minor.
Beverly Hills Police Lt. Mitch McCann said that if Garrison is prosecuted and convicted on all three charges, he could serve more than 13 years in prison.
Authorities did not say what the three teenagers were doing with Garrison the night of the crash.
The actor's attorney, Harland Braun, said he had not seen the investigation report and couldn't comment directly on the recommended charges. But he accused police of attempting to try the case "in the press."
"The real question now is, 'Can you get a fair trial when the police chief and all these policemen have already put out this version?' " Braun said.
Representatives of the district attorney's office, which will decide whether to charge the actor, said they have yet to review the recommendations and would not comment.
In a news conference Wednesday, police said Garrison had a blood-alcohol level more than 2 1/2 times the state's legal limit of 0.08%, in addition to the cocaine. Investigators determined that he was driving more than 40 mph in a 25 mph zone.
"Driving under the influence led to this tragic situation," McCann said, adding that police found no evidence of any other contributing factor in the crash.
He said police recommended the contributing to delinquency charge because Garrison allegedly offered the minors drinks and bought alcohol.
Braun said the actor recalled having two drinks that night, but added that Garrison's memory may be unclear "because he's been in a horrible accident."
Previously, Braun has said the teens recognized Garrison in the checkout line at a grocery store on the day of the accident and invited him to a party. An hour later, Garrison left to meet a woman and the teens were invited to tag along, Braun said.
The next thing Garrison recalled was waking up in a hospital, where he was treated for minor injuries, Braun said
Setian's family members issued a brief statement Wednesday through their lawyer, Paul Kiesel, saying they were "very thankful" for the Police Department's "very thorough investigation of this tragic accident." The family said it would not comment further until the district attorney's office decides how it will proceed.
Meanwhile, some of Setian's friends from Beverly Hills High School were planning a candlelight vigil by the tree where he was killed. A friend who graduated from the school last year, Isaac Bokhoor, 19, said he hoped Garrison will "be locked away for as long as possible."
Times staff writer Tami Abdollah contributed to this report.