SAN JOSE -- The prostitute accused in the robbery and killing of millionaire tech investor Ravi Kumra began testifying Thursday as the key witness against her brother and his fellow accused gangsters, describing in detail how the break-in-turned-lethal was casually planned and carried out in a single day.

It was the second time Katrina Fritz has been an informant in a homicide. The first time was in a 2006 Oakland case when she admitted tipping off two East Bay men to information that led them to kill a churchgoing woman who was a potential witness against them.

Fritz, now 33, claimed Thursday it was her brother DeAngelo Austin's idea to rob Kumra on Nov. 30, 2012. Her testimony came during a preliminary hearing for one of the defendants, Marcellous "Blade" Drummer, 26. Both have pleaded not guilty.

Fritz told Judge Linda Clark that she was a long-time prostitute in the eccentric millionaire's harem and knew the layout of his gated estate. She wasn't there during the crime, but under California law, she is still culpable because the killing occurred during the commission of felony robbery.

The robbers ransacked the 7,000-square-foot house, punched Kumra's wife, bound and gagged the couple with duct tape. They let the wealthy investor, who once owned the Mountain Winery concert venue in Saratoga, suffocate despite his wife's pleas to call a doctor.

Fritz testified that it all started when Austin called her in the morning to ask her if she'd seen Kumra lately and whether he had any money in the house. She hadn't seen Kumra for about a year.

"It was weird, out of nowhere,'' she said of the call. "I said, "maybe I should call him and see if he's there.'' I didn't want him (Kumra) to be there because it's dangerous. But DeAngelo told me not to call, (saying), "because if something happens, they'll think, 'you.'''

Asked by prosecutor Kevin Smith if she had any regrets about not warning Kumra, she said she did.

"I could, like, probably have made it better,'' she said, adding that she warned her brother and Drummer several times to "be cool'' because Kumra was "getting old."

Later that same day, she said, she helped direct her brother to the mansion when he drove down to case the place. He returned to Oakland, and they met in a parking lot, where she stopped on her way to San Francisco to pick up one of her regular johns, to give Austin a diagram she drew of the mansion. She testified that Drummer was with her brother, as was another man she couldn't see through the heavily tinted windows of Austin's BMW.

Fritz is now charged with special circumstances murder and faces life in prison without the possibility of parole or even the death penalty, if District Attorney Jeff Rosen decides to seek it. In exchange for her testimony, she is hoping for reduced charges of robbery, false imprisonment and gang enhancements that could put her behind bars for a maximum of 17 years.

Fritz is not a gang member herself, the prosecutor said. But she is charged with acting for the benefit of Ghost Town and Money Team, the Oakland gangs allegedly involved in the home-invasion robbery.

Fritz described growing up in a world where crime was king. She first became a prostitute at age 13 when she agreed to have sex with a motel manager in exchange for free rent for her impoverished mother and siblings. She began servicing Kumar when she was about 19. He paid her and at least four other women he called his "main girls'' in cash and jewelry. He also bought her one car after another, downgrading her to a Ford Escort after the first two cars were towed because they were unlicensed and she sold the third.

"She had sex with a motel manager to keep a roof over her family's head, and she had three pimps before she was 21, who beat, raped and sodomized her," said her lawyer, Ken Mandel. "In some ways, she lost the ability to say no."

Fritz said Kumra wanted her to have his child, as some of his other women had done. So, when Fritz got pregnant in 2008 with her boyfriend's child, she lied to Kumra and told him it was his so he would take care of her for the rest of her life. Then the economy took a steep dive, cutting into Kumra's fortune and prompting her to get an abortion.

She didn't find out Kumra had died until she watched the TV news the next morning. The news put her in a "panic,'' she said, so she went shopping at the mall to relax. Later, she arranged to meet Austin and Drummer, along with others who knew nothing about the crime, at an Oakland restaurant. All her brother and Drummer told her, she said, was "(expletive deleted) went bad,'' and that the unidentified third robber kept hitting Kumra while his wife screamed at them to stop. She also said Austin slipped her $2,000 under the table at lunch, which she presumed was from the robbery.

Frisk testified that her brother told her he got rid of the loot, including coins and jewelry, at an "Asian pawnship in San Francisco.'' He also gave her $40,000 from it at some point to hide for him.

Before they were arrested, both Drummer and her brother marveled that police had arrested another prostitute and a homeless alcoholic in the case, expressing relief that it wasn't them behind bars. The charges were eventually dropped against that prostitute, Raven Dixon, and the homeless man, Lukis Anderson, and both were released from jail.

Under low-key cross-examination by Drummer's lawyer Jim Blackman late Thursday, Fritz agreed that Kumra had been "generous,'' "pleasant'' and "gentle'' with her.

She said her motive for informing on her brother was to be with 8-year-old daughter and resume taking care of her other brother, who has Down syndrome. She noted that even without her testimony, the evidence against her brother is strong: His DNA was found at the crime scene, and cell phone records indicate he was in the vicinity.

She said her brother understood her rationale for helping the prosecution, indicating in a holding cell they both were in that he wasn't angry.

"He put some money on my books,'' she said, "and he told me he loved me.''

Contact Tracey Kaplan at 408-278-3482. Follow her at Twitter.com/tkaplanreport

Contact Tracey Kaplan at 408-278-3482. Follow her at Twitter.com/tkaplanreport