Superior Court Judge William Swain Lee had only two options in sentencing Capano: death by injection, as the jury recommended, or life in prison.
He was required by law to give the jury's 10-2 recommendation for execution "great weight."
Capano showed no emotion as the sentence was read and mouthed "It will be all right" to his mother and brother, Joseph, as he was being led from the packed courtroom.
"The defendant fully expected to get away with it and if not for his arrogant and controlling nature, he may have succeeded," the judge said. "He is a ruthless murderer and feels compassion for no one and remorse only for the circumstances he finds himself in today."
The judge set a June 28 execution date, however it takes an average of 8 1/2 years for a death sentence to be carried out in Delaware.
There are now 18 inmates awaiting execution in Delaware.
Capano, 49, a former state prosecutor, was convicted in January of murdering Anne Marie Fahey, who was an aide to Delaware Gov. Thomas Carper.
A member of a wealthy and influential Wilmington family, Capano admitted at trial to dumping Fahey's body in the Atlantic Ocean, but said she died at the hands of another mistress who found them together.
Capano said the other woman, Deborah MacIntyre, accidentally shot Fahey in a jealous, suicidal rage, and that he got rid of her body (dumping it from his brother's boat) to protect himself and her.
MacIntyre denied even being at his house the night Fahey died.
Prosecutors, who asked for the death penalty, alleged that Capano killed Fahey because she wanted to end her secret, three-year affair with the married man. Without a body or a murder weapon, it took years to make a case against Capano.
Finally, in November 1997, Capano's younger brother, Gerard, came forward, telling investigators he was with Thomas Capano on June 28, 1996, when the two dumped a body from his boat 70 miles off the New Jersey coast.
"No one except the defendant will ever know how or why Anne Marie Fahey died," the judge said in handing down the sentence. "It was not a crime of passion but of control.
"She could not be allowed to reject him. He chose to destroy a possession rather than lose it."
Eight inmates have been executed in Delaware since 1992, most recently on April 19, 1996, when James B. Clark was executed for murdering his adoptive parents.
The Capano case is far from over. Fahey's family has filed a wrongful death suit against Capano. They also have sued his brothers and their businesses (the family fortune was built on real estate and development), saying they helped cover up Fahey's disappearance.
Written by Todd Spangler