Story highlights Kelly Thomas, the 37-year old homeless man, died days after his arrest

Two Fullerton, California, police officers face charges

One tells Thomas: "You see my fists? They're getting ready to f--- you up."

A graphic video played at a hearing Monday to determine whether two California police officers should stand trial in the beating death of a homeless man showed them kicking and punching the mentally ill man as he lay on the ground -- screaming in pain and begging for help.

The victim, Kelly Thomas, died five days after the beating on July 5.

Manuel Ramos, a 10-year veteran of the Fullerton, California, police department, is charged with second-degree murder and involuntary manslaughter, while Cpl. Jay Patrick Cicinelli faces charges of involuntary manslaughter and felony use of excessive force in the same case.

Both have pleaded not guilty.

The black-and-white video was played during a preliminary hearing for the two officers.

It begins with Thomas -- a 37-year-old homeless man with schizophrenia -- sitting and being told by Ramos to put his feet out and hands on his knees.

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The officers were responding to a call about a homeless man looking into car windows and pulling on handles of parked cars.

In the video, Thomas is slow to cooperate.

Ramos then tells him: "You see my fists? They're getting ready to f--- you up."

Thomas, who is unarmed and shirtless, stands and another officer walks over. They hit him with their batons and hold him on the ground as he begs for help.

"Ok, I'm sorry, dude. I'm sorry!" he screams. At one point, Thomas says he can't breathe. The officers tell him to lie on his stomach, put his hands behind his back and relax.

"Ok, here, here, dude, please!" he says.

Other officers arrive.

At times, trees block the view of the camera and it's not always clear who is doing what as officers pile on top of Thomas.

One uses a Taser stun gun.

Thomas cries out for help and. toward the end of the beating, for his father: "Dad! Help me. Help me. Help me, dad."

His voice gets softer and trails off.

By the end of the video, he is lying in a pool of blood as the officers wonder out loud what to do next.

One can be heard saying: "We ran out of options so I got to the end of my Taser and I ... smashed his face to hell."

Thomas suffered brain injuries, facial fractures, rib fractures, and extensive bruising and abrasions, according to prosecutors.

The Orange County coroner listed his manner of death as a homicide and said he died after having his chest compressed, leaving him unable to breathe.

The FBI is investigating possible civil rights violations in his case.

Six Fullerton officers, including Ramos and Cicinelli, were put on paid leave after his death. The case drew widespread attention to the police department of Fullerton, located about 25 miles southeast of downtown Los Angeles.