SAN FRANCISCO (AP) _ Police are re-examining their policy on the use of pepper spray after a black burglary parolee who had been shackled, handcuffed, gagged and sprayed died on the way to the station.

``I am concerned about what, if any, contribution it made to this man dying,'' Police Chief Tony Ribera said in Thursday's editions of the San Francisco Examiner, referring to the spray.

Federal prosecutors ordered the FBI on Wednesday to look into Aaron Williams' death, already the subject of four separate city and police investigations. Local black leaders demanded a federal investigation, saying they couldn't trust the department to discipline its own.

``It is difficult for us to trust, we cannot trust, the police department because we know what some of the police do,'' said the Rev. Cecil Williams.

None of the 12 officers involved has been disciplined.

Williams' family claims that police let the 35-year-old parolee die without medical care Sunday in the back of a police wagon, hogtied, gagged and choking on pepper spray.

Williams died about an hour after struggling with 12 officers in front of his house, where police went to arrest him for investigation of a break-in at a veterinary clinic.

Witnesses allege the officers beat and kicked Williams after he was handcuffed, shackled and on the ground.

Police said Williams was high on crack cocaine when he collapsed, and the coroner's office said preliminary findings, such as the man's unusually high body temperature, support officers' arguments that the death was drug-related. No official cause of death has been announced.

Police believe Williams died during the 10-minute trip to the station, said homicide Inspector Jim Bergstrom. The family believes he lay dying, uncared for, for about 20 minutes in the back of the van, said an attorney for the man's family, Clarence Livingston.

The American Civil Liberties Union of Southern California has tracked 26 other deaths in California in the past 2 1/2 years in which victims had been subdued with pepper spray.

Departmental guidelines require officers to monitor suspects at least 45 minutes after they've been subdued with the spray, and to wash off the spray if necessary.

The ACLU's Allan Parachini said many of the victims died of suffocation after they were sprayed and restrained.

``We take the position that hogtieing someone who has been pepper sprayed is asking for a fatality,'' Parachini said.

Other department guidelines call for constant monitoring of violent suspects in apparent delirium.

The San Francisco Chronicle reported three of the officers in the case previously have been sued for allegedly using excessive force. The city settled two of the cases out of court, and the third case was dismissed because the statute of limitations had expired.

A fourth officer, who once worked for the Oakland Police Department, was accused in an internal police document by fellow officers in that city of using excessive force.

Williams was paroled from prison in December after doing time for burglary. He had three previous convictions for drug offenses and car theft.

Bergstrom said Williams fought to keep from being taken into custody becauase he feared being sent to prison for life under the state's ``three strikes, you're out'' law.