WASHINGTON (AFP) - Police have identified a suspect in the murders of a wealthy Washington family using DNA collected from the crust of a pizza delivered to their home, news reports said on Thursday.

Police said in statement that they have obtained an arrest warrant for Daron Dylon Wint in connection with the four murders, one of the most notorious crimes in recent memory in the US capital city.

Savvas Savopoulos, president and CEO of American Iron Works, a building materials manufacturer in Maryland, his wife Amy, their 10-year-old son Philip and the family's housekeeper Veralicia Figueroa were all killed at the millionaire's mansion in an exclusive section of Washington.

The stately home, with the victims bound and bludgeoned inside, was destroyed by a fire May 14 that appeared to have been deliberately set, police said.

Savopoulos's blue Porsche, which had been stolen, was found shortly after the murders, abandoned several miles from the crime scene, and also had been set ablaze, authorities said.

The Washington Post reported Thursday that the break in the case came after police matched Wint, 34, to DNA found on the crust of a Domino's pizza that had been delivered to the house on the night of May 13, as the victims apparently were being held captive.

The daily, citing sources and court records, said Savvas Savopoulos's personal assistant dropped off a package containing US$40,000 (S$53,490) in cash at the home shortly before it went up in flames.

Police said Wint is wanted for first degree murder in the case, and news reports said authorities have not ruled out that the crimes were committed with the help of accomplices.

The violence of the offenses shocked and horrified Washington, at least in part because they occurred in a tony section of the city rarely touched by deadly crime.

The neighborhood is home to numerous embassies and diplomatic mansions as well as the official residence of Vice-President Joe Biden and his wife.