INDIO, Calif. -

The penalty trial of a Desert Hot Springs gang member convicted of killing a U.S. Marine and a teenager starts today.

Emilio Manuel Avalos, 35, faces a possible death sentence for the Dec. 19, 2001, slaying of 20-year-old Marine Cpl. Henry Lozano and the Dec. 21, 1994, shooting death of 17-year-old Jahi Collins. In addition to the murder charges, Avalos was also convicted of the attempted murder of Collins' friend, Bobby Wilson, who was left paralyzed in the 1994 gunfire at Wardman Park in Desert Hot Springs.

The trial started in August, and Avalos was convicted last month. The penalty phase of the trial, during which jurors will recommend either the death penalty or life in prison without the possibility of parole, will begin this morning.

``We're here because (Collins and Wilson) went to a park to hang out with girls and got ambushed in the most cowardly of ways ... and because Henry Lozano had the audacity to date a girl who used to date the defendant,'' Deputy District Attorney Pete Nolan told jurors during his closing argument.

Nolan said that when Collins and Wilson were ``at their most vulnerable, they were ambushed by the defendant and two of his West Drive Locos'' gang associates. ``What you know is someone unloaded 14 rounds into Jahi Collins' car,'' he said.

Nolan said the 2001 killing of Lozano was prompted by Avalos' former girlfriend, who told Avalos she loved the Marine. She said Avalos responded by vowing to kill Lozano.

On Dec. 18, 2001, Lozano spent the night at the girl's Desert Hot Springs apartment, ``got up the next morning and he was shot ... in ambush style,'' Nolan said. ``Somebody drove up beside him, no doubt, and unloaded into his car.''

One of Avalos' attorneys, Bill Dittman, said witnesses corroborated that Avalos was in San Fernando on Dec. 19, 2001, and that Avalos didn't have a motive to kill Lozano.

``Emilio Avalos testified and told each of you he did not commit these crimes. Emilio Avalos is innocent of these crimes,'' Dittman said in his closing argument.

On the stand, Avalos denied telling his former girlfriend and three friends that he killed Collins and shot Wilson, and testified that he never said he would go after Lozano.

Avalos' other attorney, David Macher, contended that Wilson didn't know who shot him, and the assailants wore masks.

``(They) confirm that the identity of the gunman was not known then and is not known today,'' Macher said in his closing argument.

He said Wilson wouldn't have concealed the gunman's identity, and when he testified in the trial that he knew it was Avalos, he was lying.

``Revenge -- that's what Bobby Wilson wanted,'' Macher said.

There was ``a whole universe of potential shooters out there, and that universe was a whole lot larger than Emilio Avalos,'' he said.

A judge consolidated the Lozano and Collins murder cases in 2007. The law allows combining separate crimes when they're the same type or have similar attributes, according to district attorney's spokesman John Hall, who said that both shootings showed a distinctive method of operation and evidence pointing to Avalos.