A Long Island, N.Y., man was charged with murder yesterday after a trooper making a routine traffic stop on Interstate 95 found a body in the back seat of the man's car, Virginia State Police said.

Charles E. Baeza, 51, was held without bond in Fairfax County jail in the shooting death of his wife, Ruth Baeza, 52, of Franklin Square, N.Y.

The shooting apparently stemmed from a dispute between the couple, who had been separated, sources said.

The couple's private ordeal played out in public fashion before crawling lines of northbound rush-hour motorists, police said.

At 5 a.m., just before daybreak, Trooper F.B. Ingham sat writing a ticket in his cruiser, which was parked on the southbound shoulder of I-95, just north of the Newington exit. Ingham was startled by a white sedan that nearly smashed into his cruiser as it sped down the highway.

Turning on his flashing blue light and siren, Ingham pursued the car, eventually pulling it over just south of the Newington exit. He made his way to the car and began talking to the vehicle's driver.

During the conversation, Ingham noticed an arm lying beneath some newspapers in the back seat, police said. He asked the car's driver who the person in the back seat was. The driver said it was his wife, police said. Ingham then asked the driver to wake up his passenger.

According to a description of the incident by police spokeswoman Lucy Caldwell, Baeza allegedly said, "I can't . . . . She's dead." At that point, Baeza made statements that police have interpreted as an admission of guilt in the woman's death, Caldwell said.

Police believe Ruth Baeza was shot in New York, sources said. It was unclear yesterday whether Fairfax County court officials or New York officials would prosecute the case, said Fairfax Commonwealth's Attorney Robert F. Horan Jr.

Police were unable to say how Baeza and his wife were employed, and relatives of the couple could not be reached for comment.

"This is an unusual case," Caldwell said. "The trooper could have been killed" if the car had rammed his cruiser. "But," she added, "if the car had not had been driven recklessly, we don't know where Ruth Baeza's body might have ended up."