TEXARKANA, Texas (AP) _ A bomb exploded and killed a drug company president when he switched on the ignition of his Mercedes-Benz, but police said Tuesday they had no suspects and company officials were baffled about a motive.

Walsh-Lumpkin Drug Co. President Daryl Crouch, 36, died instantly in the blast Monday night, and his wife and 10-year-old daughter were burned as they frantically tried to pull him free, police spokesman Earl Cox said.

''We literally, honest-to-God literally, have nothing to hang our hats on,'' said Walsh-Lumpkin spokesman Ron Gray. ''I was as close to the man as anyone could be, but nobody has any idea why something like this happened.''

Jan Crouch, 35, who was treated for burns and released from Wadley Regional Medical Center, would not talk to reporters. The couple's daughter, Sandy, was hospitalized in fair condition Tuesday with burns on her face, hands and back, hospital spokeswoman Ann Beaty said.

Cox said police had no suspects.

''It's too early in the game to say anything. We just don't know anything yet,'' said Police Chief Lee Spradlin.

The Crouches' Mercedes exploded shortly before 7 p.m. Monday in the parking lot outside Walsh-Lumpkin's single-story brick offices on State Line Avenue, which divides Texas and Arkansas.

Crouch, whose charred body was sprawled halfway out of the driver's side door, apparently had just switched on the ignition. Sandy was a passenger in the Mercedes, but Mrs. Crouch already had gotten into her car, which was parked nearby, police said.

''It shook us pretty bad. We thought we were on fire,'' said Lorann Ables, who works at the Taco Tico restaurant on the Arkansas side of the street.

A passerby pulled Mrs. Crouch from the burning car as she tried to rescue her husband, Ms. Ables said.

''She was on fire with a little blaze on her. She tried to get back into the car to pull the man out, but they wouldn't let her,'' she said.

Mrs. Crouch and her daughter ran around the car and screamed as they tried to pull Crouch from the wreckage, said Eloise Elmore, front desk clerk at the Best Western motel across the street.

Agents from the U.S. Bureau of Alcohol, Tobacco and Firearms roped off the building Tuesday as they probed the wreckage of the Mercedes and seven other cars damaged in the blast.

Evidence from the scene will be sent to the ATF explosives laboratory in San Francisco, said Bob Switzer, acting agent in charge of the bureau's Dallas office.

Switzer and Cox would not say where the bomb was attached to the car or how it was made.

Gray said company officials had no reason to believe the explosion was related to an extortion attempt against the pharmaceuticals supply company last summer.

Walsh-Lumpkin received an anonymous letter in August that officials interpreted as a tampering threat aimed at an unspecified product. The threat was investigated, but no evidence of tampering ever was found.

Crouch, a member of the Texarkana Airport Authority and the son-in-law of Walsh-Lumpkin owner W. Pearson Walsh, was preparing to take over leadership of the company, Gray said.

He also was president of Tri-State Hospital and Surgical Supplies of Joplin, Mo., and executive vice president of Texarkana-based Humco-Emerson Laboratories.

Former Mayor Durwood Swanger said Crouch was ''active in the Chamber of Commerce and everything else that was pro-Texarkana.''

''I can't imagine him having any enemies,'' said airport manager Roy Miller.

Ron Hertlein, president of Security Savings Association, where Crouch was on the board of directors, said the killing ''almost sounds like an underworld type of thing. ... Daryl Crouch and Pearson Walsh wouldn't be associated with anything like that.''