An autopsy report Monday showed the wife of prominent defense attorney Daniel Horowitz (search) died from a blunt force trauma to the head, the Contra Costa sheriff's department said Monday night. Her death was ruled a homicide.

Earlier Monday, police were zeroing in on a possible suspect in the baffling murder, according to a family friend, though sheriffs said talk of an imminent arrest in the case was premature.

Meanwhile, a judge declared a mistrial in a murder case against one of Horowitz's clients.

Horowitz — a TV legal pundit who became a familiar face during the Scott Peterson (search) double murder trial — found his wife, Pamela Vitale (search), dead Saturday night at the entrance of the mobile home they shared on property where they were building their dream estate, authorities said.

Attorney Ivan Golde, a longtime friend and co-counsel in a high-profile trial Horowitz is currently involved in, said police were getting closer to solving the case.

"There is a potential suspect, but it's not a former client," Golde said Monday on his way in to the courtroom.

Horowitz was interviewed as part of the investigation and was said to have been cooperative, said Jimmy Lee, a spokesman for the sheriff's department, at a press conference late Monday afternoon. The couple's neighbor, Joseph Lynch, was also interviewed.

Golde told FOX News on Monday that he didn't think the person responsible for the crime was someone associated with Horowitz in his professional life. Instead, he said he believed the person responsible was someone the couple knew and someone who knew Vitale would be home and Horowitz would not, he told FOX News.

San Francisco Chronicle editor Phil Bronstein (search) said on a FOX News Channel program Monday that a reporter told him an arrest had been made, but the paper quickly retracted that comment, citing a misunderstanding between Bronstein and the reporter. As of Monday evening, there was still no arrest.

Lee said Monday he hadn't learned anything about a possible suspect or a motive, and he called Golde's statement premature.

"We do have some leads that we are following up on, but I wouldn't want to characterize something as we're getting closer to an arrest," he said.

Meanwhile, a judge declared a mistrial in a murder case against a woman being defended by Horowitz, citing heavy news coverage of Vitale's slaying. Horowitz was not in court as the judge postponed the trial for Susan Polk (search), who is accused of murdering her therapist husband.

As a lawyer who defended drug dealers, killers and other serious criminals, Horowitz was worried about his safety, Golde said Sunday. Authorities told FOX News that he had a surveillance system on the property and carried a gun.

"This is a real tragedy, these are good people," Golde said of Horowitz and Vitale. In a Monday news conference, he called the ordeal "an absolute nightmare."

Horowitz and Vitale were, by all accounts, a happily married couple and she was a charming, intelligent woman. Their lives, friends said, revolved around each other.

After the death, a deputy was stationed Sunday at the bottom of the steep driveway leading to the home. A canopy of trees blocked views of the property, located on a sprawling hillside estate about 20 miles east of San Francisco.

Horowitz called 911 Saturday evening to report that his wife was dead, Lee said.

Another lawyer friend, Robert Massi, said Monday on NBC's "Today" show that he had seen Horowitz earlier Saturday and that Horowitz had an alibi during the day.

"He was with me for a couple of hours and met with his defense team about 11 o'clock on the Susan Polk case," Massi said. "In the afternoon he dropped paperwork off at the hotel where I was staying."

"Everything was fine. ... It's just devastating to think that nine hours later the man finds his wife like this," Massi added.

Horowitz and Vitale married about 10 years ago; both had been previously married. Vitale, 52, a former high-tech marketing executive, worked at her husband's law practice managing databases.

Horowitz, 50, appears frequently on FOX News Channel, CNN and MSNBC and became best known for providing a defense perspective in Peterson's murder trial.

Opening statements were presented just last week in the trial of Polk, accused of murder in the 2002 stabbing death of her psychologist husband in the pool house of their Orinda home. Polk's husband, Felix, was her therapist when she was a teenager, and she claims she killed him in self-defense.

Vitale sat in the front row of the courtroom last week during Horowitz's opening statement, Golde said. "She was down to earth and she was cool and believed in what Dan was doing," Golde said.

Horowitz also defended former Ukrainian Prime Minister Pavlo Lazarenko (search) in a multi-count money-laundering and fraud trial. In May, a judge threw out half of the convictions against Lazarenko, who is under house arrest in the San Francisco Bay area.

Horowitz also represented Steve Williams (search), the fan who snagged Barry Bonds' 700th home run ball, in a lawsuit to determine who could keep the ball. A judge allowed Williams to auction it.

FOX News' Claudia Cowan, Catherine Donaldson-Evans and The Associated Press contributed to this report.