RIVERSIDE, Calif. -

An ex-con who ambushed a Riverside police officer at the end of a foot chase, beating and then shooting him execution-style with his own gun, was convicted today of first-degree murder and other felonies.

Jurors deliberated 3 1/2 hours before finding Earl Ellis Green guilty of killing 27-year-old Officer Ryan Patrick Bonaminio on Nov. 7, 2010.

During the penalty phase of the trial, which is slated to begin May 21, the eight-man, four-woman jury will determine whether to recommend a death sentence or life in prison without the possibility of parole.

The defendant, dressed in a dark blue suit, showed no reaction as the verdict was read. Several members of Bonaminio's family wept.

Outside the courtroom, the slain officer's father, Joe, and other immediate family members, along with friends and supporters, applauded prosecutors Mike Hestrin and John Aki for their handling of the case.

``We still have a little bit ahead of us, but thank you all,'' Hestrin told the crowd of about 30 people.

Green's penalty trial is expected to last several weeks and will ``basically be like starting a different trial,'' Hestrin said.

Riverside County Superior Court Judge Jean Leonard directed the prosecution and defense to be prepared to begin submitting motions next week on
evidence and witnesses.

Along with the first-degree murder count, the jury found true special circumstance allegations that Green killed a peace officer and committed a murder to avoid arrest. The panel also found him guilty of vehicle theft and being a felon in possession of a gun.

The defendant's attorneys conceded that Green killed the officer, but argued it was second-degree murder, which would have ruled out a death sentence.

During his closing statement Thursday, Hestrin described Bonaminio's death as ``unspeakably violent'' and said the evidence was overwhelming that Green shot the patrolman at point-blank range.

``It was a cold-blooded, callous execution of a police officer who was just doing his job,'' the prosecutor said.

Green's public defender, Gail O'Rane, argued the 46-year-old parolee was acting on impulse and never planned to kill Bonaminio.

``Mr. Green is trying to get away,'' O'Rane said. ``He is just reacting to the circumstances. If Mr. Green had been acting rationally, he would have gotten out of there.''

According to trial testimony, Green had stolen a semi truck with no trailer from a Rubidoux facility that Sunday evening and got into a fender-bender with a motorist on Market Street, near the Pomona (60) Freeway.

The ex-con fled the accident scene, prompting the other driver to call police, at which point Bonaminio responded to the area and stopped Green adjacent to Fairmount Park.

Green jumped out of the truck, ran through the park and into the parking lot of the nearby Center for Spiritual Living on Ridge Road. As Bonaminio caught up with the defendant, the officer lost his footing in a freshly watered planter next to the center and fell in the mud.

The sole eyewitness to the shooting, Stephen McQueen, testified that Green immediately pounced on the lawman, smashing him in the head three times with a steel pipe.

Bonaminio was largely incapacitated by the blows, and Green could have used the opportunity to get away but instead went for the injured officer's .40-caliber Glock pistol, racking the semi-automatic firearm to ensure a bullet was chambered, Hestrin said.

According to testimony, Bonaminio struggled to his feet, put his hands in front of his face and shouted at Green, ``Don't do it!''

Hestrin said the defendant fired two rounds, both of which missed, then approached to within two feet of Bonaminio and -- after a five-second pause -- fired a third shot into the top of the officer's head.

``This was an unspeakably violent and brutal act,'' Hestrin told jurors.

The foot chase, assault and shooting transpired over 90 seconds. Green was seen on Bonaminio's patrol unit dashboard camera fleeing from the truck and returning. The pistol was found at the defendant's girlfriend's house, and the steel pipe with his fingerprints on it was left next to Bonaminio.