PAWTUCKET — A police officer shot and killed a 30-year-old man yesterday morning after he apparently brandished a “Samurai-style” sword and later struggled naked with the officer inside an apartment building, according to Police Chief George L. Kelley III.

The police say Jason M. Swift, of 71 Lupine St., was shot two times by an officer and was pronounced dead at the scene. Some of the circumstances surrounding the shooting remained unclear late yesterday, such as whether Swift was armed at the time.

Kelley withheld the names of the three officers involved in the incident pending further investigation from the department, the state attorney general’s office and state police. The officers have been placed on administrative leave.

It was the third fatal shooting involving a Pawtucket police officer in the last seven months.

“We’re not proud or happy when we have to do it, but sometimes we have to do it,” said Kelley, about the number of officer-related fatalities in the past year. “It is a busy city.”

Kelley said police responded to a call at 7:31 a.m. yesterday of an “emotionally disturbed individual with a knife” outside an apartment building at 71 Lupine St. The nine-unit building is at the corner of Broadway and Lupine, close to Exit 29 of Route 95.

Two patrol officers found Swift — who was 6 feet, 5 inches tall and weighed 300 pounds — acting “erratic” and “threatening” outside the building, said Kelley. Swift was fully clothed and swinging a sword.

Kelley said that officers, following the department’s protocol for use of force, attempted to subdue Swift using pepper spray and physical force. “This was a very large person,” Kelley said.

But Swift eluded officers, and went inside the building to the third-floor apartment where he lived with his mother, Betty Swift. Officers then called for back-up and another patrolman arrived.

What happened next is still unclear, the chief said.

The officers apparently pursued Swift into the apartment. At some point, Swift took off his clothes. He indicated that he would cooperate with the officers and agreed to be handcuffed, said Kelley. There was then “a violent struggle” in the apartment. One officer fired two shots (Kelley would not say where the shots hit Swift).

By the time had run into the apartment, Swift had abandoned the sword, which was found outside, so it was unclear if he was armed at the time of the shooting, according to Kelley.

The officer who fired at Swift was treated for bruises at the scene. Kelley described him as a young man who had been with the department 2½ years and had no prior record of fatal shootings.

Kelley said that Swift, a 1996 graduate of William E. Tolman High School, in Pawtucket, had been having “mental problems in the last few days.”

On Monday night, the mother of one of Swift’s children filed a report at police headquarters regarding an incident of domestic violence. Kelley would not elaborate on the incident, only saying that it took place in a car in front of Swift’s apartment between 11 p.m. and 12 a.m. Monday night.

He would not say whether police believe Swift’s confrontation with police officers was directly linked to the earlier incident. “It’s too early to say,” he said.

Police cordoned off Lupine Street for about four hours yesterday morning. “It was complete mayhem,” said Chet Zubu, of 45 Lupine St.

Residents said they were acquainted with Swift’s mother who worked at the J & L Dollar Discount a few blocks down on Broadway, but not Swift himself. Employees at J & L declined to comment, saying that it was a difficult time for friends and relatives of the family. The owner of the apartment building, who would identify himself only as Jim, said he knew the Swifts well but declined to comment.

Steven Brown, executive director of the Rhode Island Affiliate of the American Civil Liberties Union, said the latest shooting points to a “troubling” pattern in the department, which polices a city of about 73,000 residents, according to the 2000 U.S. Census.

“Pawtucket police have shot more people in the past year than most police departments shoot in an entire decade,” he said. “It should send up red flags to the department to do a thorough review of protocol.”

Including yesterday’s shooting, Pawtucket police have fatally shot four people in the past two years. Last summer, the department was involved in two fatal shootings in two days. The police have been cleared of any wrongdoing in those previous instances.

On July 2, 2006, Patrolman Russell B. Amato shot and killed James Wilcox, 34, of 22 Beecher St., Pawtucket, after the police said Wilcox tried to run the officer down with his van.

On July 26 of last year, Pawtucket Patrolman Derrick Smith shot and killed Bridget DeGrafft, a 49-year-old Attleboro woman who police said hijacked an SUV at knifepoint. DeGrafft led police on a chase down the highway and tried to run down Smith with the vehicle.

The next day, July 27, three Pawtucket police officers opened fire on Jason Audette, a 34-year-old burglary suspect who, police said, refused to drop his .32-caliber pistol. Pawtucket Patrolmen David L. Holden, Mark A. Ramos and Christopher E. LeFort fired 11 rounds into Audette, who had apparently raised his gun at the officers but did not fire a shot.

pmarcelo@projo.com