Chunren Chen, the restaurant worker who hacked a fellow employee with a meat cleaver during an argument at a Palo Alto restaurant in 2009, reached a plea deal on Monday that could send him to prison for five to 12 years.

Chen, 64, has admitted he attacked co-worker Zezhong Yang at the Jade Palace restaurant in Palo Alto on May 27, 2009. Records show he had a previous arrest for a "similar" assault with a deadly weapon in Alameda County in 1997.

He was charged with attempted murder and aggravated mayhem for the attack on Zezhong Yang, a chef, after he struck him several times with a meat cleaver in the restaurant's kitchen.

Yang sustained a nearly 5-inch gash to his face and a cut to his carotid artery. He had lacerations to his back, shoulder, thumb and neck and a fractured wrist, police reported.

Chen faced life in prison if convicted.

But his case proved to be more complicated than a simple crime of rage. At a May 8, 2010, hearing, it was revealed that Chen had been tortured and "re-educated" by the Communist regime in China during the Cultural Revolution of the 1960s.

Chen later had a mental breakdown and was hospitalized, according to the judge's notes. A psychotherapist who examined him in December 2009 concluded that Chen likely has post-traumatic stress disorder, attention-deficit hyperactive disorder and anxiety disorders, according to the notes.

Chen escaped from China and went to Spain and Bolivia prior to coming to the United States, according to the documents. He immigrated without documentation to California around 1996. He worked at both Jade Palace and Ten Fu, a Menlo Park restaurant.

He was arrested in 1997 in Alameda County for assault with a deadly weapon, in what was described as a "similar incident" at another restaurant, the notes indicate. The case was not prosecuted, police said.

In the 2009 incident, Chen admitted to Palo Alto police that he struck Yang several times with the cleaver but claimed self-defense, police reported.

He said he and Yang had animosity between them since he started working as a busboy at the restaurant two months prior. Yang did not treat him with respect, he said.

Chen said Yang hit him with the broomstick and he swung the meat cleaver at Yang's face in response.

Chen's conviction under the plea deal will be for attempted murder, his attorney, Ruben Munoz, said.

"I think the judge will have an open mind. he doesn't know what sentence he will hand down," Munoz said of Santa Clara Superior Court Judge Douglas Southard.

Munoz said he hopes that Southard will choose leniency and will sentence Chen to five years. With time already served, Chen would remain in prison for about two more years, he said.

Chen "is looking forward to finishing his sentence and to going to China," he said. Chen is an undocumented immigrant, according to court papers.

The mayhem, assault with a deadly weapon and premeditation charges were dropped in large part because of concerns about Chen's age and health issues, Santa Clara County Deputy District Attorney James Demertzis said.

Yang, the victim, also found testifying at the preliminary haring emotionally taxing. "He wanted to avoid a trial," Demertzis said.

Chen agreed to admit to the attempted murder and infliction of great bodily injury, he said.

Judge Southard indicated during Monday's haring that an eight-year sentence could be appropriate, Demertzis said.

Chen's sentencing will take place June 20.