When Al Biscoe heard about a high-speed police chase leading to the fatal burning of 11-year-old Melanie Nicholson last Sunday, his first thought was that the child's death was "too high a price" for society to pay to catch a speeding motorist.

Biscoe himself paid a high price as the result of a high-speed police chase through Arlington and downtown Washington on Sept. 27, 1979, following an Arlington bank robbery. Biscoe was an innocent bystander at 19th and E streets NW when a car that police were chasing hit a parked car and careened into Biscoe, severing one of his legs on the spot. The other leg had to be amputated a few days later.

Since his accident, Biscoe said, he has come to believe that death and injury resulting from high-speed chases are almost always needless. He thinks police should abandon virtually all high-speed chases long before the public becomes endangered.

Some police officials, however, see the issue of the high-speed chase in a different light. While they say public safety is ultimately the paramount concern, they also see an injury like Biscoe's and a death like Nicholson's -- the 15th fatality in a D.C. police chase since 1969 -- as tragic but unavoidable side effects of their duty to enforce the law.

Last Sunday, D.C. police chased a 1970 Cadillac for more than four miles after police radar clocked it at 82 mph on Suitland Parkway. With two police cruisers in pursuit, the Cadillac reached speeds estimated at up to 90 mph before hurtling through the Third Street tunnel, smashing the rear of the Nicholsons' idling car and killing Melanie, who had been on her way to sing in the junior choir at Corinthian Baptist Church in Northwest Washington. Her father Clarence, a church deacon, was critically injured and is in fair condition at the Washington Hospital Center.

Melanie's death once again raised the crucial question of when police should start -- and abandon -- a high-speed chase. Throughout the region and the nation, official police guidelines vary among departments. A chase like last Sunday's might have ended differently had it begun in Arlington, where departmental regulations do not allow high-speed chases by police in pursuit of traffic violators unless the suspects have also committed a felony serious enough to cause injury or death.

Regardless of written rules, however, the decision to start or stop a chase usually boils down to a split-second judgment made by a police officer travelling at high speed, police officials stress. That decision-making process -- in which the lowest-ranking officer and not the superior may have to make the life-and-death choice -- is rarely examined at law enforcement institutions, they say.

"I don't see what could have been done differently" in the Nicholson case, said D.C. Police Capt. Wayne A. Layfield, commander of the traffic division. "The officers were correct" in chasing a motorist who was already considered a "menace" when he was clocked at 82 mph, Layfield said. If police don't make a strong effort to stop a speeding motorist, he said, "how do you know a driver won't end up killing three or four or five people down the road?"

An estimated 300 to 500 persons are killed and as many as 5,000 are injured every year as a result of high-speed police chases, according to studies compiled by Brian Traynor, a police traffic specialist with the National Highway Traffic Safety Administration. Those numbers are only guesswork, though, because no comprehensive national study of the problem has ever been done and nobody has defined specifically what constitutes a "chase," he said. NHTSA has just requested money to study "the pursuit problem," he said. In the District, no statistics on accidents or nonfatal injuries are kept on police chases, officials said.

Reconstructing Sunday's wild four-mile pursuit, Layfield said virtually all of it was on lightly travelled highway and therefore posed relatively little risk to the public. Lt. Mario Savilla and Officer James Harding reported their patrol cars' speeds at up to about 70, never getting closer than about six car lengths to the suspect, Layfield said. He said the officers were about to abandon the chase when the suspect entered the three-quarter-mile-long tunnel. He said they knew that a third police cruiser was waiting on the Massachusetts Avenue end of the tunnel and that traffic on the avenue would make further high speeds impossible. But the Cadillac did not slow down, police said.

Even though the police maintained control of their own vehicles, Biscoe said that, in his view, the chase still caused the young girl's death. "The police, under these circumstances, are saying in effect to the public, 'We know you don't mind paying the price of a person dead to catch a speeder.' And I am saying, 'Yes, that's too high a price.' " In his own case, Biscoe has filed a $25 million damage suit against Arlington and D.C. officials. "In my case, the thieves had stolen $3,000, and let me tell you, $3,000 does not replace my legs."

Biscoe, 49, who lives in Potomac and works at the National Science Foundation, said police should be willing to let a fleeing suspect go and to attempt by other methods to catch up later. The only exceptions, he said, should be for someone like "an unbalanced murderer" who presents immediate danger to others.

Such methods, though, would undermine the law, said a D.C. police spokesman, Lt. Hiram Brewton. Failure to pursue speeders would create open season for traffic accidents, he said. Police can't just take license plate numbers and try to catch people later because they often couldn't prove in court who was driving the car, he said.

"There is no solution," said Layfield. "The public may get outraged" by a chase-related death, "but the public would get outraged if we didn't chase lawbreakers."

Police departments differ on their chase policies, ranging from no written rules at all for some smaller departments, no written rules at all, to general guides in some, to others that tell officers what speeds and circumstances are acceptable for high-speed pursuit, according to reports gathered by the National Criminal Justice Reference Service in Rockville.

In the District, police regulations allow high-speed chases in pursuit of fleeing suspects in any felonies, misdemeanors and traffic violations. Stricter policies are in effect elsewhere in the area. In Arlington County, for example, police are not allowed to pursue a suspect vehicle unless they its occupant has committed a felony which may involve death or injury. Other Virginia and Maryland departments have guidelines similar to Arlington's.

The International Association of Chiefs of Police guidelines, a model for some departments, specifically instruct officers to weigh the seriousness of the suspected crime during a chase. While the District does not spell that out, Brewton said, all officers are expected to use common sense in deciding that some crimes merit hotter pursuit than others.

The District's regulations regarding chases, in language similar to that of other police departments, state that "whenever it becomes evident that unnecessary property damage or injury to citizens or members of the department may result, . . . that pursuit shall be immediately discontinued."

But the regulations are of little comfort to Biscoe and Lois Nicholson, mother of 11-year-old Melanie.

"I don't know whether the police did right or wrong," Nicholson said last week. "I just know that I don't want it to ever happen again to anyone else."