In the space of eight months, Philadelphia Police Officer Larry Shields twice made the decision to shoot.

The first time, Shields shot and wounded a man who he said had pointed a Glock at him in a North Philadelphia house. The wounded man has since sued the city, but he was arrested after the encounter and police Internal Affairs and the District Attorney's Office have backed Shields.

The second time, Shields fired upon an unarmed man in the victim's Southwest Philadelphia house.

This spring, the city paid the wounded man $2.5 million to settle a lawsuit, the biggest such payout in connection with a police shooting in at least a decade.

But again, the District Attorney's Office ruled it a justified shooting.

In fact, a spokeswoman for the office, which reviews all cases of police gunfire, said she did not believe prosecutors had found fault with any on-duty police shooting since Seth Williams became D.A. in 2010.

The police Internal Affairs unit has also overwhelmingly found officers justified in shootings, top police officials say.

Police gunfire is newly under scrutiny now that Police Commissioner Charles H. Ramsey has asked for federal assistance in a comprehensive review of the use of deadly force by the department.

Ramsey took the step amid a violent week in which officers shot seven civilians, killing four. In six of the shootings, the suspects were brandishing handguns; in the seventh, an officer shot and killed a man who lunged at officers with a knife.

He also sought the study after reviewing comprehensive statistics that showed police fatally shot or wounded 52 people last year, the highest figure since Ramsey became commissioner in 2008.

That was a 50 percent jump over the 35 people shot and wounded the previous year.

In recent years, taxpayer payments to settle lawsuits filed by shooting victims have also soared. Since 2009, the city has paid $11.6 million to resolve such suits, with annual payouts far higher than in previous years, records show.

Even though police and prosecutors have cleared the officers of wrongdoing, city lawyers have settled more than 50 shooting civil suits in recent years. The lawyers say they were taking a tactical step to avoid the financial risk of courtroom verdicts.

That spending was paced by the $2.5 million paid to settle a suit by victim Stephen Moore, whom Shields shot in November 2011 in Southwest Philadelphia after entering the man's home in an investigation.

Shields was not on duty Friday at the 18th Police District, and top police officials said he would not be made available for an interview.

In the 2011 shooting, Moore's in-laws, who were at odds with him, called 911 to say someone was in the house without permission. Responding, Shields pushed open the front door, which Moore had left unlocked. That triggered a burglar alarm.

When Moore went downstairs to check on the alarm, Shields shot him. Shields reportedly told investigators he fired after Moore made a threatening movement toward his waist. Moore denied that and said Shields had shot without warning, and without identifying himself as a police officer.

The city settled the suit as the case was moving toward trial. threMoore's attorney, Robert J. Levant, said the settlement was fair and just. "He received significant gunshot wounds," Levant said. "He suffered loss of significant functions of his hand and arm, as well as permanent lung damage."

The second-largest settlement of the decade was a $1.5 million payment last year to John James, a motorcyclist shot in the leg by Officer Richard DeCoatsworth in 2009.

In a subsequent trial, a jury found James guilty of reckless endangerment and fleeing an officer but acquitted him of the more serious charge of aggravated assault.

DeCoatsworth is the former hero officer who survived a shotgun blast to the face and who sat next to the first lady when President Obama addressed Congress in 2009. Last month, the officer was charged with raping two women at gunpoint.

Paul J. Hetznecker, a Philadelphia lawyer suing the department over an unarmed man police shot dead in a stolen car two years ago, said reviews by police Internal Affairs and prosecutors had been virtually meaningless for many years.

"It's an entrenched culture that has failed to train and to investigate excessive force over decades," he said. "It has reached a crisis point."

In a news conference Friday, Ramsey said that even with the flurry of gunfire, Philadelphia appeared to be on track to have fewer police shootings this year compared with last year. So far this year, police have shot 22 people.

"I expect our officers to protect themselves and the public," Mayor Nutter said at the news conference.

For Ramsey, there was a bit of deja vu in his request for help.

In 1999, a year after he took command of police in Washington, Ramsey asked the U.S. Justice Department to study that department's firearms policies. He did so after the Washington Post found D.C. police shot and killed people at a higher rate than any other major city police force.

Over time, that behavior changed. By 2000, D.C police use of firearms had fallen by half compared with three years earlier.

In requesting help for Philadelphia, Ramsey cited reviews undertaken in recent years in New York City and Las Vegas.

In New York, the police commissioner asked the RAND Corp., the research nonprofit based in California, for help in early 2007.

The timing was significant. In a notorious case the previous November, five police officers fired 50 shots into a car driven by 23-year-old Sean Bell, killing him. Though the officers involved were ultimately acquitted of criminal charges, the city paid $7 million to settle a wrongful-death lawsuit.

In its review, Rand urged the NYPD to dramatically improve its firearms instruction, moving beyond mere target practice to "scenario-based training and role-playing workshops."

In Las Vegas, officials of a U.S. Justice Department program known as COPS - for Community Oriented Policing Services - reached out to local police after a five-part newspaper series and the Nevada ACLU raised questions about a series of police shootings there. Among other findings, the Las Vegas Review-Journal reported in 2011 that in Las Vegas, much as in Philadelphia, department investigators had cleared officers 99 percent of the time.

In the end, Las Vegas police and federal officials, assisted by private consultants, released a sweeping report with 75 findings and recommendations for reform.

The study urged Las Vegas to strengthen its investigations of deadly-force cases and to create a new office to follow through on all reforms. The department also agreed to make public detailed reports on each shooting.

Contact Mark Fazlollah

at 215-854-5831 or mfazlollah@phillynews.com.

Inquirer staff writer Sulaiman Abdur- Rahman contributed to this article.