The Philadelphia medical examiner's office has ruled Monday that Temptations singer David Ruffin's death was an accident caused by an adverse reaction to cocaine.

Ruffin, 50, the former lead signer of the Motown group, died early June 1 after a limousine driver dropped him off at the emergency room of a city hospital.The driver, who was a friend of Ruffin's, was Donald Brown, and police said he has been located and questioned.

Police said Brown, 35, apparently drove Ruffin to a crack cocaine house earlier. Ruffin collapsed in the drug house and was taken to the hospital, where he died about 90 minutes later.

The crack house in west Philadelphia was sealed off following Ruffin's death and police searched it last week.

An official with the medical examiner's office said: "He died of an adverse reaction to a drug - cocaine. His death was ruled accidental." There were no additional details available.

Police said they do not expect charges to be filed in the case, although some $40,000 of Ruffin's money has apparently disappeared.

Ruffin's New York agent, Ruth Bowen, said Ruffin had the proceeds from a recent tour in England in a money belt. She said the former Motown star also was carrying a briefcase containing personal papers and an unknown number of British traveler's checks.

Police later recovered the briefcase, but the traveler's checks and cash were missing.

Bowen said the missing money was earned by Ruffin and former Temptations members Eddie Kendricks and Dennis Edwards during the British tour. Ruffin had collected the money from the tour promoter and was supposed to wire Kendricks, another former Temptation, and Edwards their shares over the weekend. Bowen said the concert tour took in nearly $300,000.

But authorities found only $53 on Ruffin after Brown drove him to the Hospital of the University of Pennsylvania in a borrowed limousine.

According to police reports, Brown drove Ruffin to the house between 10 and 11 p.m. May 31 in a limousine borrowed from a friend, Linster "Butch" Murrell.

Police said Ruffin apparently collapsed at the crack house and was driven, unconscious, to the hospital by Brown, who left immediately.

Ruffin had a history of drug problems dating to the 1960s, and was arrested in 1988 on a drug charge. But following a stay in a drug treatment center in 1989, Ruffin claimed to have kicked the habit and had resurrected his sagging career along with Kendricks and Edwards.

Ruffin had lived in Philadelphia since 1989 with his girlfriend, Diane Showers.