HAYWARD -- Closing statements were under way Tuesday in the state's murder case against a Hayward man accused of killing three teen passengers during a fatal downtown police chase and crash.

Leo Olguin, on trial in Alameda County Superior Court, is charged with three counts of murder as well as robbery, evading arrest and felony DUI ending in death or major injury in connection to the Dec. 23. 2009, fatal crash.

Police say Olguin skipped out of a halfway house while on probation and drove a Mazda through a red light about 12:15 a.m. on the day of the incident. As officers began chasing him, he crashed into a Safeway big rig. The collision on A Street at Foothill Boulevard killed three passengers in his car -- Vanessa Hurtado, 16, Andrew Falcon, 17, and Dominic Hall, 18.

Olguin, 25, suffered minor injuries, perhaps because he ducked as the Mazda plowed through the big rig's undercarriage. A fifth person in the car, a woman, was seriously hurt. Olguin was arrested at the scene.

Trial testimony began Dec. 10 before Judge Roy Hashimoto at the Hayward Hall of Justice. Last week, forensic toxicologist Bill Posey told jurors that Olguin had a cocktail of drugs in his system during the wreck. Traces of alcohol, cocaine, marijuana and methamphetamine were found in his blood about an hour after the crash, Posey testified during the second day of testimony.

A blood sample revealed a blood-alcohol level of 0.07, but Posey estimated his level at the time of the crash would have been 0.09, just above the state's legal limit of 0.08.

The cocaine and alcohol found in Olguin's system were ingested within hours of the wreck, and the meth likely a few days earlier, Posey said.

The robbery charges are tied to an incident that took place about 30 minutes before the crash. Testimony revealed three people were robbed at gunpoint in a residential neighborhood near Harder Road and Mission Boulevard.

During a preliminary hearing last year, a police detective testified that Olguin's statement changed several times, but Olguin indicated that he was scared of going back to jail and that an unspecified back-seat passenger also urged him to make a break for it, showing Olguin a gun in his hand.

Olguin is being held without bail at the Santa Rita Jail.

Closing statements are expected to continue into Wednesday with jury deliberations to follow.

Contact Natalie Neysa Alund at 510-293-2469. Follow her at Twitter.com/nataliealund.