SAN JOSE (CBS SF) -- Three jail guards were found guilty Thursday afternoon by a Santa Clara County Superior Court jury of the second-degree murder of mentally ill inmate Michael Tyree, 31, at San Jose's Main Jail in 2015.
Jereh Lubrin, 30, Rafael Rodriguez, 28, and Matthew Farris, 28, had been on trial since March for the fatal beating of Tyree the night of Aug. 26, 2015.
Numerous inmates in nearby cells testified that they heard Tyree pleading with the guards, "I'm sorry" and "Stop," before he was found dead in his cell, covered in feces and vomit with lacerations to his liver and spleen, which was nearly severed in half.
The trio was also charged with the assault under color of authority of 48-year-old schizophrenic inmate Juan Villa the night Tyree died, and Lubrin was charged for a separate assault on Villa on July 25, 2015.
But Judge David Cena declared a mistrial on those charges Thursday afternoon when the jury did not arrive at a unanimous verdict on the two non-fatal assaults.
The jury foreman said jurors were split 10-2 on the August assault on Villa and about half and half on the July assault.
Jurors agreed that further deliberation would not help them arrive at a unanimous verdict on either of those counts. A hearing about them will be held on June 28.
Tyree's sister, Shannon Tyree, sobbed in the front row of the audience where she sat with District Attorney Jeff Rosen and other observing prosecutors.
The guards' families wept as the three men in tailored suits were handcuffed in court immediately following the verdict reading, calling out "I love you," "Te quiero mucho" and "Be strong. Remember who you are."
The guards each face a sentence of 15 years to life in prison for the murder conviction.
Sheriff's officials did not say whether the guards would be held in another county's jail before their sentencing on Sept. 1.
"We stand here because three men whose very job it was to protect him treated Michael Tyree as something nameless, and they beat and killed him as though he were worthless," Rosen said at a news conference outside the courthouse, in view of the jail where the murder took place almost two years ago.
"He is gone now, but Michael Tyree's tragedy was worthy of our outrage," Rosen said.
Santa Clara County Sheriff Laurie Smith, who filled out the two back rows of the audience with top sheriff's brass on Thursday, spoke outside the courthouse of the "broad transformation" the jail system has begun to undergo since Tyree's death.
"This tragic incident has served as a catalyst in our ongoing progressive efforts within our custody bureau," Smith said. "We will not be defined by the actions of these three individuals."
A Blue Ribbon Commission undertook a public examination of custody operations, and county government has been reviewing the commission's recommendations since that review.
"We have made substantial progress since the night of Aug. 26, 2015, when Michael Tyree was found dead in his cell," Santa Clara County Board of Supervisors President Dave Cortese said in a statement.
"But much more work needs to be done to ensure that our jails are safe for inmates, corrections officers and visitors," Cortese said.
The sheriff's internal investigation of the three guards, who were out on bail on $1.5 million each and have been on paid administrative leave since their arrests, is still underway, Smith said.
Thanking prosecutors "who made the impossible possible today" in a statement, Shannon Tyree said, "Michael was a human being. Those jurors recognized that. He was loved. He mattered then and he will continue to matter with this verdict."
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