It will take six to eight weeks for tests to confirm whether the Delaware County man killed Tuesday in a police shooting had Huntington's disease, sources said.

An autopsy released Friday on Joseph A. Pacini, 52, showed he died of multiple gunshot wounds, the medical examiner's report said.

Pacini was in his car when he allegedly tried to run down officers who were attempting a traffic stop in Upper Darby. In response, police opened fire.

According to Michael J. Chitwood, Upper Darby superintendent of police, Pacini was wounded five times in his head, neck, shoulders, and chest. At least 22 shots were fired, Chitwood has said.

Shortly before the shooting, police attempted at Pacini's Clifton Heights home to serve a warrant for public threats he made against law enforcement.

Pacini's friends and family have said he suffered from Huntington's disease, a hereditary, disabling brain disorder.

Tests to confirm the disease's presence and to determine whether Pacini had been under the influence of alcohol or drugs have been sent out for further study and will not be available for six to eight weeks.

An investigation to determine whether the shooting was justified is continuing, said Emily Harris, spokeswoman for the Delaware County District Attorney's Office. It is being conducted by a special investigations unit, which is standard protocol, Harris said.

The Haverford Township officers who were involved in the incident have returned to duty, said Deputy Chief John Viola. Upper Darby officers involved are expected to return Monday, said Chitwood. Calls to Clifton Heights police were not returned.

Even though police did not have information that Pacini may have had Huntington's disease, neither department was second-guessing its actions.

Viola said officers took every measure possible to ensure the safety of police. The SWAT team was brought along in case Pacini had barricaded himself in his home, he said.

While there was no indication Pacini owned a gun, that didn't mean he didn't have one, said Viola.

No weapons were found on Pacini or in the car, Chitwood had previously said.

Viola said the situation Tuesday evolved so quickly there was no time for officers to try to intervene with a more peaceful resolution. All Haverford Township officers and one of the two Upper Darby officers involved in the incident had been specially trained in crisis intervention, police said.

"Our goal was to get him under arrest and get him into the system," said Viola, adding that they "feel badly for the family."

Viola said police could not let Pacini return to the LA Fitness facility where he often worked out.

"It appeared [from YouTube videos] he was trying to draw us into the gym for a public confrontation," Viola said.

Police were concerned that, if he returned to the workout facility, Pacini may have involved or injured patrons.

mschaefer@phillynews.com

610-313-8111 @MariSchaefer