WILMINGTON, Del. (AP) _ In a startling courtroom turnaround, a politically connected lawyer on trial on charges of murdering his mistress admitted through his attorney Monday that he disposed of the body but insisted the death was an accident.

The admission came on the opening day of Thomas Capano's trial in the slaying of Anne Marie Fahey, who was Gov. Thomas Carper's secretary.

It was the first time Capano has even acknowledged that Ms. Fahey is dead.

Ms. Fahey was last seen at dinner with Capano at a restaurant in Philadelphia in 1996. Her body has never been found, and Capano had long maintained that he knew nothing about her disappearance.

Prosecutors believe that Capano, a 49-year-old former prosecutor and gubernatorial aide from a wealthy family of developers, killed Ms. Fahey because she was trying to end their three-year secret affair. Prosecutors have no murder weapon but have suggested that Capano shot her.

In his opening statement Monday, defense attorney Joseph Oteri said Capano and his brother Gerard dumped Ms. Fahey's body off the New Jersey coast. Oteri did not specify what caused her death _ only that Capano did not murder her.

``Anne Marie Fahey died as the result of an outrageous, horrible, tragic accident,'' he said.

Oteri said another person who was in Capano's house the night Ms. Fahey died knows what happened. He refused to name the person, saying that it would be revealed at trial.

``Tom Capano lied to everyone who ever asked about Anne Marie Fahey except for one person who knows the whole truth,'' Oteri said.

The prosecution, in its opening statement, told the jury that Capano planned for months to kill Ms. Fahey and dump her body at sea.

Prosecutor Ferris Wharton said Capano bought a gun through another lover and purchased a cooler two months before Ms. Fahey disappeared.

``That cooler he bought in April became what he always intended it to be: It became Anne Marie Fahey's coffin,'' Wharton said.

Wharton said Capano, a married father of four daughters, had become obsessed with Ms. Fahey during a secret, three-year relationship. When she tried to break it off, Capano couldn't stand it, Wharton said.

Oteri attacked Gerard Capano's credibility, noting he made a statement to prosecutors only after they raided his house and threatened him with federal drug and weapons charges.

He called Gerard Capano ``a typical, screwed-up rich kid'' whose habitual drug and alcohol abuse has made his memory unreliable.