Prosecutors launched the murder trial of Alberto Alvarez with an emotional opening statement on Monday morning: They played 911 recordings and showed photos of slain East Palo Police Officer Richard May to the jury and a packed courtroom audience.

Alvarez, 26, is charged with murder with special circumstances and possession of a firearm as a convicted felon relating to the Jan. 7, 2006, slaying.

May was killed by a shot to the face, allegedly after chasing Alvarez, whom witnesses reported had engaged in a brawl with another man at the nearby Villa Taqueria.

Steve Wagstaffe, San Mateo County deputy district attorney, told jurors that Alvarez shot May three times -- twice into his bullet-proof vest and once in the shoulder -- before walking over the dazed officer laying on his back in a Weeks Street driveway and executing him with a fourth shot at point-blank range.

Wagstaffe said a coroner determined the other three shots were not life threatening.

Alvarez knew he had a choice to make; to submit to Officer May and face jail for being a convicted felon in possession of a firearm or to shoot his way out, Wagstaffe said.

"He made the horrible choice to shoot his way out. Even when he put the officer down on his back, dazed, he goes up and fires again," Wagstaffe said.

Alvarez, looking pallid and thin and wearing a light-blue shirt, stared blankly at Wagstaffe throughout most of his opening statement, which lasted about an hour, while many in the courtroom shed tears.

Defense attorneys Charles Robinson and Eric Liberman said outside the courtroom that they will prove that Wagstaffe's opening statement was factually and forensically inaccurate.

"There is no question in our minds that there was no execution," Liberman said.

They said they will prove that May fired at Alvarez first and that the first shot Alvarez fired hit May in the face and that the officer was dead after the first shot, contrary to Wagstaffe's statements.

Alvarez "was chased and beaten and shot" (in the leg) before he responded, the attorneys said.

The trial continue Monday afternoon with the defense's opening statement and testimony of the first witnesses.