Petersen quits as CSI's Grissom

Petersen took a break from the 2006-7 series of CSI so he could star in a play

Actor William Petersen is to leave CSI: Crime Scene Investigation, having been with the TV forensics drama since its first episode eight years ago.

He will still make guest appearances as Gil Grissom but his character will no longer be seen on a regular basis, two of the show's executive producers said.

His final episode is likely to be broadcast early next year as part of the programme's 10th series.

Several characters will return in storylines leading up to his departure.

These will include Grissom's former colleague and girlfriend Sara Sidle, who is played by former ER star Jorja Fox.

Lady Heather and the Miniature Killer - two characters who have featured in long-running storylines - will also be brought back.

New character

The decision to leave was Petersen's own, executive producers Carol Mendelsohn and Naren Shankar said.

His character was "a man who has suffered a great deal of loss recently", Mr Shankar told the Associated Press.

Petersen's character leads a team of forensics investigators in Las Vegas

The storyline leading to his departure would tie in with Grissom "thinking about the next phase of his life", he added.

And he insisted the Las Vegas-based programme would cope without Petersen, saying: "Shows lucky enough to go this long inevitably have to deal with this kind of change."

A new male character will join CSI in place of Petersen, Mr Shankar added.

"Whoever comes in and joins the team after Grissom is going to be a different guy. But the nature of the show and what fans get out of it, that's not going to change."

The programme is broadcast by CBS in the United States and seen around the world, with Five screening it in the UK.

The success of CSI: Crime Scene Investigation has led to two spin-off versions, set in Miami and New York.

Petersen's publicist was unavailable for comment when contacted by the Associated Press.