MARTINEZ -- With hands trembling and speaking in a soft, halting voice, Rafael Zarate described to a jury Monday how, consumed with jealous rage, he stabbed to death a waitress in the bathroom of the Richmond restaurant where she worked.

Zarate, 44, said he never planned to kill 30-year-old Jensy Romero when he tracked her to Angie's Bakery and Restaurant on Sept. 20, 2011, but only wanted to discuss with her their off-and-on relationship that played out over 15 months -- while both were also seeing other people.

"I was so obsessed, I was so in love with her," said Zarate, a Mexican immigrant who testified that he entered the United States illegally and falsified documents to get work as a welder.

Zarate is charged with murder and stalking.

He testified that he began dating Romero in June 2010, even though he knew she was seeing someone else, and that she broke up with him in August 2011. He admitted deluging her with text messages and phone calls and showing up unannounced at her Richmond apartment and workplace.

"I was all the time looking for her," he said.

He found her the evening of Sept. 20, 2011, arriving at Angie's before she started her shift. She arrived just before the manager and a lone customer departed, and the two were left alone.

Zarate said when Romero called a friend for help, he took her cellphone. He said she "was screaming like crazy," and that after he returned the phone to her, she ran for the women's restroom.

She tried to block the door, Zarate testified, but he pushed his way inside. Again, they fought over the cellphone, he said. When he demanded to know whether she was seeing someone else, he said, she told him yes.

"She was saying, 'Are you happy now?' " Zarate said.

At that point, Zarate testified, he recalled a customer at Angie's giving Romero a hug and a kiss on the chin.

"I got so angry. I was super, super jealous," he said.

He testified that he reached into his boot to retrieve an approximately 8-inch knife he carried "for protection." With the two face to face inside a dark restroom, he "stabbed her two times hard," Zarate testified.

When prosecutor Rachel Piersig, on cross examination, asked Zarate whether he was aware Romero suffered four stab wounds, the defendant seemed confused.

"She had four?" he asked. "I thought she had three."

Police located Zarate at a friend's house in San Leandro. After a lengthy standoff during which he said he drank heavily, Zarate charged police with what he knew to be a BB gun, hoping, he said, that police "could shoot me, that they could kill me." He was hit by a beanbag projectile and two bullets and taken into custody.

The trial resumes Wednesday with closing arguments.

Contact Gary Peterson at 925-952-5053. Follow him at Twitter.com/garyscribe.