from www.tmz.com – This is the man arrested for the $2 million extortion plot against David Letterman. Robert “Joe” Halderman — a well-respected producer for “48 Hours” — was busted outside CBS headquarters in NYC for attempted grand larceny in the first degree.

Until recently Halderman was living with Stephanie Birkitt, Letterman’s former assistant. We’re told Letterman was having a relationship with Birkitt but ended it before his son was born in 2003.

additional: One of the women at the center of the David Letterman alleged extortion case is Stephanie Birkitt, his former assistant — according to the search warrant obtained by FOX 5 New York. And, the warrant says, Birkitt was the suspect’s girlfriend and we’ve learned she was living with him until recently.

According to the warrant, the suspect, “48 Hours” producer Robert “Joe” Halderman, sent Letterman a package which allegedly included treatments for a screenplay with supporting materials.

The warrant goes on to say the “supporting materials” included copies of parts of a diary and correspondence belonging to Birkitt.

Halderman allegedly sent more documents, including letters, emails and photos.

On September 23, Halderman allegedly told undercover cops he wouldn’t make the diary public if Letterman anted up $2 million.

Letterman acknowledged on his show last night he had sexual relations with female members of his staff.

Birkett has been a regular on Letterman’s show

additonal:We’ve learned Robert “Joe” Halderman was arrested yesterday outside the CBS headquarters in NYC, and it was news to the people inside who make the news.

Our sources say the Manhattan D.A. played the investigation close to the vest and people inside the building were baffled when the highly-respected producer was cuffed and hauled off in the David Letterman extortion case.

As we already reported Halderman had a relationship with Stephanie Birkitt and lived with her. But we’re told they had broken up “recently.” We do not know who ended the relationship, but Halderman allegedly was in possession of Birkitt’s diary, correspondence and photos — which he says incriminated Letterman.

People connected with the network tell us Letterman did have a relationship with Birkitt, but the word is that it ended before Letterman had his baby in 2003.

additional: Robert “Joe” Halderman — the man accused of trying to extort David Letterman out of $2 million — had to pay a pretty penny in child support, according to court documents obtained by TMZ.

According to the divorce settlement agreement he signed with ex-wife Patty Montet in 2004, the “48 Hours” producer was required to pay $6,800 a month in child and spousal support for three years. That amount was reduced to $5,966.66 in May 2007.

Their house was sold and the proceeds divided during the divorce. And the credit card bills, totaling approximately $13,500, were split down the middle. Halderman agreed to pay for the unreimbursed medical bills for his two children. He was also required to maintain life insurance.

The agreement also provided that the court would have the power to order payment of the children’s college education by either parent. One of the children is now 18 — college age. The other child is 11.

The wife — Patty Montet — filed for divorce on grounds the marriage was “broken down irretrievably.”