A Michigan woman and her father were shot to death as they sat in a parked car outside the Washington Hilton Hotel last night in what police described as a murder-suicide.

Police said they believe that Beth L. Katz, 54, of East Lansing, Mich., shot Robert Shaw, 84, of the District, in the head and then turned the gun on herself. Shaw died at the scene, and Katz died at 9:33 p.m., shortly after being taken to George Washington University Hospital.

The shootings outside an entrance to the hotel ballroom occurred about 30 yards from where President Ronald Reagan was shot March 30, 1981, as he left the hotel at 1919 Connecticut Ave. NW through a side door onto T Street.

A handgun was found on the back seat next to where Katz had been sitting in the dark red, late-model Ford Taurus station wagon, said Jose Acosta, commander of the Third Police District. Shaw, in the front passenger seat, had been shot at least once. His body, clad in a green Windbreaker and tan pants, remained in the car for more than 1 1/2 hours after the shooting.

Police said Katz and Shaw were traveling together visiting the city in Katz's car. Shortly before 9 p.m., the two drove to the driveway of the hotel ballroom and parked. She got out of the driver's door, entered the rear passenger's door and shot her father, police believe. Neither were listed as hotel guests.

Police were still unclear about a motive.

Employees and hotel guests heard at least three shots shortly after 9 p.m., Acosta said. The car was parked against a curb along the circular driveway outside the ballroom, which faces T Street, he said.

"It's a pretty frightening experience," said hotel guest James Quade, of Denver, who returned from dinner last night to see a dead body in the Taurus. "I'm a guest here. It's scary. I've never seen anything quite like this. I talked to a cabdriver. He said this is a pretty good area."

Acosta affirmed that. "This is a very, very quiet, safe neighborhood," he said.

"It's a bad situation," said Bill Edwards, general manager of the Hilton. "I've been here 24 years. . . . [The shooting] has nothing to do with this building. It could have happened in Chevy Chase. Whatever their issue was, it ended here."

Staff writer Phuong Ly and staff researcher Heming Nelson contributed to this report.