VAN NUYS, Calif. — Twenty years after filming episodes entitled "Murder for Me" and "Woman Trouble" as the small-screen gumshoe Baretta, Robert Blake hatched a scheme worthy of Hollywood to get rid of his pregnant girlfriend, a private investigator testified Wednesday.

"We're going to hire a doctor, we're going to abort her, and if that doesn't work, we're going to whack her," said Blake according to William Welch, testifying in Blake's preliminary hearing for murder. The hearing is to determine whether Blake will stand trial for the killing of Bonny Lee Bakley, the woman whom he eventually married after she gave birth to their daughter.

Welch testified he had worked on "routine P.I. stuff" for the actor for a decade, and agreed to accompany Blake on a meandering, out-of-form walk that took them down near the Los Angeles River one Saturday in October, 1999.  But the murder plot caught him by surprise.  "I said Robert, are you out of your f**king mind?"

The next day, Welch said, Blake called to say he'd abandoned his murder plan.  Bakley gave birth to the child, and she and Blake married in November, 2000. 

But prosecutors claim Blake never really forgot the scheme, and took matters into his own hands when he shot Bakley twice behind a Studio City Italian restaurant on May 4, 2001.  Blake is charged with murder, conspiracy to commit murder, and solicitation of murder.  He could face life in prison.

During a taped interview aired on ABC's "20/20" Wednesday night, Blake professed his innocence and speculated that someone Bakley scammed years ago could have been the one to shoot her. He also questioned the role of the LAPD, which waited more than a year before arresting him last April 18.

"Only a celebrity can say that police are framing me with that much evidence in his face," said Eric Dubin, who represents Bonny Bakley's estate.  Bakley's sister, Margery Bakley, and Bakley's grown daughter, Holly Gowran, sat with Dubin in court Wednesday. Bakley's family has filed a wrongful death lawsuit against Blake.

The murder plot wasn't the only scheme that Welch revealed while on the stand—and it wasn't the only scheme seemingly culled from Blake's days as "Baretta."  Another time, the actor, who once filmed an episode called "Setup City," devised a plan to plant some cocaine at Bakley's Beverly Hills hotel.  Welch would call his friends with the Los Angeles Police Department, and Bakley—who was on probation for fraud related to her mail-order pornography business—would be out of the picture.

Welch said he quashed this plot too.  "I told him that this was another one of his real bad ideas," said the witness.

Welch's testimony came after prosecutors played a tape Bakley recorded in which Blake berates her for getting pregnant with their child.  "You swore to me, you promised me, you promised," says Blake on the recording.  "You said, 'Don't worry, Robert, no matter what, I will have an abortion.  You never have to worry about me getting pregnant.'"

The tape was initially allowed into evidence despite a rule barring illegally obtained evidence from court (Bakley recorded the conversation without Blake's consent, which is illegal in California) but Superior Court Judge Lloyd Nash decided later in the hearing that he will consider the matter further.

Blake's attorney, Thomas Mesereau, Jr., won't be required to call witnesses during the preliminary hearing, as the prosecution has the simple hurdle of proving they have enough evidence to try Blake for murder, not convict him.

That hasn't stopped Mesereau from putting on a tenacious defense through cross-examination, including an extended cross of a medical examiner on Wednesday morning and a contentious battle with Welch the investigator.

Mesereau's most pointed attack came when the lawyer asked Welch repeatedly why he continued working for Blake, even after he thought he wanted his wife dead. 

"Didn't you think you were working for a potential killer?" asked Mesereau.

"I think I talked him out of it," replied Welch.

In preliminary hearings in California, police officers are allowed to testify what witnesses and interview subjects have told them—normally verboten under hearsay rules. 

Thanks to the hearsay exception, Sergeant Charles Knolls of the Los Angeles Police Department was able to testify about what a diner witnessed at the Italian restaurant that Bakley and Blake visited shortly before Bakley's death.

Hairdresser Michael Dufficy first recognized Blake that evening because he had a full head of hair, testified Knolls.  Blake was, in fact, pulling at that full head of hair with both hands, and had an "odd" expression on his face.

Dufficy, according to the officer, also saw the "nervous" Blake head into the bathroom—and when the hairdresser later made his own visit, he noticed that someone had vomited pasta and spinach into the wastebasket. 

Then came the turkey baster. On cross-examination from Mesereau, Knolls told the court about his discussions with Bakley's ex-husband, Paul Gawron, who said he had inside knowledge of Bakley's lonely hearts scheme.

According to Gawron, Bakley surfed from husband to husband (he knew of five), and wasn't beyond using pregnancy as a means of snaring a mark.  She even once tried impregnating herself with sperm she dumped into a turkey baster, Gawron said. 

Bakley's shady side-business of mail-order pornography is expected to form the backbone of Blake's defense should the case go to trial. Mesereau continued plumbing Knoll's conversations with Gawron, eliciting that Bakley once hired financial investigators to inspect Blake's financial background.

Of course, if Blake is found not guilty, he could still grab a page from his days as a TV cop.  Consider the first Baretta episode ever: "He'll Never See Daylight Again."    The synopsis: "Baretta vows revenge on the hoodlum whose thugs murdered his girlfriend."