When Antwann Jackson visited his old neighborhood last week, he was hit by more than a dozen gunshots.

In broad daylight on a Monday afternoon, while he was in the 7100 block of Race Street in Homewood, at least three bullets struck the 21-year-old man. He later died from a wound to the abdomen.

On Saturday evening at a residence on Cora Street in Homewood, a McKeesport man was fatally stabbed in what police said was a domestic dispute.

And last night a man was gunned down in an Allentown bar.

The three were Pittsburgh's 55th, 56th and 57th homicide victims of 2008 -- the same number as last year's total, putting the city on pace for the highest number of homicides in a decade.

At the same time, police have seen a sharp drop-off in the number of arrests connected to homicides. The Pittsburgh Police Bureau's clearance rate was 46 percent for January to September, down from 75 percent for all of last year. The rate was 96 percent in 2004, when 43 of 45 homicide cases were cleared.

Mr. Jackson, who was living in Penn Hills before he died, had much in common with many of the city's other homicide victims. He was a young black man. He was killed by gunfire. And police have not arrested a suspected shooter.

Of the victims, 50 were black and 47 died in gun violence. The average age was just over 28.

Only 25 cases have been "cleared," meaning police have made an arrest or otherwise determined the cause of a murder.

"I do think there is cause for concern," police Deputy Chief Paul Donaldson said. "We try to reduce the homicide rate every year."

Yet he and other officials are careful not to be alarmists. They said there is no simple explanation for the increase in killings; nor is there one for the falling clearance rate.

Many long-term problems are still in play, including a lack of two-parent households, easy access to guns and a reluctance for witnesses to come forward after a shooting.

Meanwhile, other crime indicators show positive changes: The number of gun assaults in the city has dropped 17 percent this year, and the total number of gun crimes has fallen 5 percent, Chief Donaldson said.

In other words, there have been fewer shootings in the city of Pittsburgh this year. But the shootings that do occur are deadlier.

Crime statistics are often malleable, and exact figures can be difficult to pin down. By another police count, the number of homicides in Pittsburgh for 2008 has already reached 64.

But police officials say some of those incidents likely won't be included when the bureau makes its year-end report to the FBI.

Police shot three of the 64: David Price, 30, was killed after he fired at detectives outside the Spaghetti Warehouse restaurant in the Strip District on March 21; Justin Jackson, 19, was killed after he shot a K-9 officer in Mount Oliver on May 6; and Nang The Nguyen, 46, was shot when he approached an officer with a meat cleaver on Atwood Street in Oakland on May 23.

Another case involved self-defense, when, according to police, a cab driver shot Marvin Harden during an attempted robbery March 1 on Somers Drive in the Hill District.

Police also are excluding the death of Matthew Scott Delanko, 19, who they say was killed last month on Brunots Island when his friend was joyriding in a truck and hit him.

A sixth case involves a homeless man, Anthony Malcolm, 43, who died this month, more than a week after a passer-by found him wounded on Hamilton Avenue in Homewood. Police initially said they suspected he'd been beaten, but they now think his death was accidental. The Allegheny County medical examiner's office is awaiting results from toxicology tests.

Excluding the Homewood stabbing on Saturday and the Allentown killing last night, that brings the official number down to 55, according to police Cmdr. Thomas Stangrecki, who oversees the bureau's major crimes investigations division.

The figure could fluctuate even without any more homicides in 2008. It already includes at least two victims who died this year from injuries they received in prior years. Police also are counting the case of Andriane Clowney, 36, who was shot in the face and chest in the 7500 block of Formosa Way in Homewood on Oct. 17, 2004. She died at the end of last year.

"Homicide detectives are doing everything they can to solve these cases," Cmdr. Stangrecki said. "Sometimes they're not solved overnight."

The bureau's homicide squad has 22 detectives. And investigators from other units, such as narcotics, are spending 60-day assignments with homicide to help with the case load.

Often police know the names of suspects, but they can't make arrests without the help of witnesses. Many are unwilling to cooperate with police because they fear retaliation, or they adhere to the code of "no snitching."

"We have a number of killers who are just walking around the neighborhood today," said Rick Swartz, executive director of the Bloomfield-Garfield Corp.

Allegheny County District Attorney Stephen A. Zappala Jr. is considering more outreach to inform the public about witness protection programs run by city and county police.

Last month, Mayor Luke Ravenstahl and city Councilman Ricky Burgess announced the creation of the Pittsburgh Initiative to Reduce Crime, which is modeled after a successful Boston program.

Its focus is a unified, overwhelming response from law enforcement and social service groups to instances of violence. If one member of a neighborhood gang shoots, then all members become targets.

Officials have dedicated $200,000 to bring the program here.

Valerie Dixon, an antiviolence advocate whose son, Robert, was shot to death in 2001, said the effort will require long-term commitment and focus from communities and police.

"If you do your part, it will work," she said. "If somebody drops the ball on this, it's not going to work."

Last week, three City Council members proposed legislation requiring that owners report lost or stolen handguns to police, an approach that faces legal battles in Philadelphia and was rejected by the Pennsylvania General Assembly in April.

The explanations for the city's gun violence are almost as numerous as the victims. But one likely dominates: Many neighborhoods face the breakdown of the two-parent family, or young single parents, leaving children without structure and discipline.

"The homicides are flowing from young men who have never learned how to settle a difference without pulling out a gun," Mr. Swartz said. "We need to start talking about out-of-wedlock birthrates."

Many young black men have few educational or employment opportunities in their neighborhoods, and some turn to selling drugs. That leads them into street rivalries, where guns are the norm.

"This atmosphere of hopelessness can be a breeding ground for violence," Mr. Burgess said.

Antwann Jackson, last week's shooting victim in Homewood, grew up in that environment. As a child, he was "silly and fun-loving," said Barbara Anderson, 47, the mother of one of Mr. Jackson's longtime friends.

He and a group of boys would often converge on her house to play. Or they would accompany her to the Monroeville Mall.

Yet Ms. Anderson, who has moved from Homewood and now lives in Plum, said she never met Mr. Jackson's father. She said the father of her children was murdered in 1990.

In December of last year, Mr. Jackson and two others crashed their car trying to flee police in the Strip District.

As Mr. Jackson tried to run from the car, he pulled a loaded Glock pistol from his waistband and threw it under a Port Authority bus, according to a criminal complaint. Three officers cornered him at Liberty Avenue and 16th Street. One punched Mr. Jackson in the head as he tried to pull away; another used a Taser on Mr. Jackson.

Police recovered about $30,000 worth of cocaine from the car.

Last month, Mr. Jackson pleaded guilty to carrying a firearm without a license and resisting arrest. He was to serve six to 23 months in a halfway house, according to his attorney, James Wymard.

But as many as four shooters in a gray Jeep Cherokee opened fire on Mr. Jackson last week in Homewood. Police say he may have been on a bicycle at the time. He was unarmed.

"That part of him I don't try to think about," Ms. Anderson said. "I wish he never got involved with that. He was such a sweet young man."