VIRGINIA BEACH, Va. (AP) _ A woman worried that she could be the next victim in the Washington-area sniper shootings saw a suspicious blue car but didn't tell police ``because they were looking for a white van.''

A police officer spoke to John Allen Muhammad, who was driving a blue car near one of the shootings, but let him go.

A dispatcher got a call from someone claiming responsibility for the attacks, but tried to refer him to another agency. The caller hung up.

Testimony in Muhammad's capital murder trial has been replete with such reminders of missed opportunities to end the three-week series of attacks in which 10 people were killed.

``These are heartbreaking things,'' said former FBI profiler Clint Van Zandt. ``These are things that police officers and FBI agents are beating themselves in the head with and saying: 'My God, if only we would have, should have, could have. We might have gotten them sooner, if only.'''

The trial enters its third week of testimony Monday as Muhammad faces charges in one of the killings, that of Dean Harold Meyers, who was shot at a Manassas-area gas station on Oct. 9, 2002.

Prosecutors are introducing evidence in 16 shootings in Maryland, Virginia, Alabama, Louisiana and the District of Columbia in an effort to show that Muhammad is responsible for multiple deaths and engaged in a form of terrorism _ necessary conditions for the two death penalty charges against him. They are scheduled to continue calling witnesses this week.

Muhammad, 42, and 18-year-old Lee Boyd Malvo, who goes on trial separately Nov. 10, were arrested Oct. 24, 2002, at a Maryland highway rest stop. They had been sleeping in a 1990 blue Chevrolet Caprice that authorities say was adapted so someone concealed inside the car could fire a rifle through a hole in the trunk.

Authorities didn't ask the public to look for such a car until shortly before the arrests, focusing instead on descriptions of a white van or a white box truck at some shootings, but several witnesses have testified they saw that car at shooting scenes.

Christine Goodwin saw a blue car at a gas station in Spotsylvania County on Oct. 11. It had peeling paint, darkly tinted windows, New Jersey tags and was parked ``cockeyed'' away from the pumps.

``Everything about that car was wrong,'' she testified.

Goodwin, fearful because of the shooting spree, said her first instinct was to tell police about the car. Asked why she didn't, she replied: ``Because they were looking for a white van.''

She later heard that a man had just been killed at that station. She didn't call police until Oct. 23.

Van Zandt said some things such as car descriptions are bound to be missed in such wide-ranging investigations, involving multiple states and multiple crimes.

But he said there are lessons to be learned from the sniper investigation, such as making sure everyone who might hear from a suspect is prepared to handle the call.

A police dispatcher from Rockville, Md., testified that she was alone and besieged by calls on Oct. 15, when one male caller told her: ``We have called you three times before, trying to set up negotiations. We have got no response. People have died.''

Amy Lefkoff said she tried to refer the caller to police in Montgomery County, Md., where the sniper task force was based, but the caller hung up.

``I was very busy,'' Lefkoff testified. ``I was just going through the motions.''

Prince William County Police Officer Steven Bailey said he spoke to Muhammad near the scene of Meyers' killing, but let him drive off in a Caprice from a restaurant parking lot where police believe the sniper fired the shot that killed Meyers a half hour earlier.

Bailey said Muhammad told him police had directed him into the lot as they secured the crime scene. Actually, police had been barring cars from entering the lot.

``I didn't catch on,'' Bailey said. ``I wish I had.''