Phil Spector is on $1m bail

Sheriff's officers in California say they will not be ready to present their case by 3 March, when Mr Spector is next due to appear in court.

If that happens, the court date will have to be postponed.

The legendary producer was arrested on suspicion of first degree murder two weeks ago after actress Lana Clarkson, 40, was found dead at his home.

No formal charges have yet been filed and Mr Spector, 62, is free on $1m bail.

Once the sheriff's department's investigations are finished, a district attorney is due to decide in court what charges, if any, will be filed.

Lana Clarkson was shot in the face

Lieutenant Dan Rosenberg of the Los Angeles County Sheriff Department said such a lengthy probe was not unusual in a murder case.

"It's because we want to complete a very unbiased and comprehensive investigation," he added.

"It takes time to get all the evidence we analysed and back to us, and to interview people we feel we need to interview."

One of the leading forensic experts in the US, Dr Michael Baden, has been brought in by Mr Spector's lawyer, Robert Shapiro, to work on Ms Clarkson's post-mortem.

Both men worked on the murder trial of American football star OJ Simpson.

A friend of Mr Spector, Los Angeles lawyer Marvin Mitchelson, said earlier this week he expected the producer would say Ms Clarkson's death was accidental.

"I've spoken with various individuals connected with the case and I'm 100% certain it's not a homicide," he said.

Ms Clarkson was found at Mr Spector's mansion in Alhambra on 3 February. She had been shot in the face.