Shootings by police in Pennsylvania should be investigated by independent law enforcement agencies, and officers involved in such incidents should be publicly identified only if they are charged with a crime, the Pennsylvania District Attorneys Association said Tuesday.

The recommendations were among several promoted by the prosecutors' group as it released what it called a "first in the nation" set of guidelines designed to establish statewide standards on how law enforcement agencies investigate and react to such incidents.

The guidelines come as police-involved shootings nationwide have become "among the most salient law enforcement issues of this generation," Lebanon County District Attorney David Arnold and Chester County District Attorney Thomas Hogan wrote Tuesday in an op-ed article in the Inquirer.

The prosecutors' association did not specify how often police-involved shootings occur in Pennsylvania. A tracker compiled by the Washington Post - based on news accounts, public records, and independent reporting - cited 17 across the state this year.

Last week, Gov. Wolf vetoed a bill that would have barred officials from releasing the names of police officers involved in shootings for at least 30 days after the incident or when an investigation is concluded. Critics had complained that withholding such information could damage efforts at police accountability and transparency.

The District Attorneys Association holds no official authority, but serves as a unified voice and resource for the dozens of county prosecutors elected across the state. It says its recommendation to withhold identities of officers who do not face criminal charges "follows the general rule that citizens who are not charged with a crime are not identified publicly." In a footnote, the guidelines say there may be "limited circumstances" under which it could still be appropriate to release an officer's name. The footnote does not elaborate.

The recommendations also call for shootings to be investigated by an outside agency. "The use of the independent agency avoids any appearance of bias," the report said.

While the guidelines are not specific, because they must be tailored to every situation and district attorney's office, they offer a checklist of things to do, including using technology such as 3D mapping to process the shooting scene, offering counseling to officers involved, leaving the police union out of the investigation, making "a very case-specific decision" about whether to release audio or video footage, and releasing information to the public after the investigation is complete.

Unlike in Philadelphia, where District Attorney Seth Williams announced he will release investigative files, the statewide guidelines say simply that a district attorney should report findings to the public.

While an investigation is ongoing, the guidelines suggest, a district attorney should consider giving a "preliminary statement ... for the public to understand the basic issues involved in the investigation."

The prosecutors group also released statements from Pennsylvania community leaders and relatives of people killed by police in which they praised the new guidelines.

"This opens the curtains to the process which hopefully will get better buy-in to the outcome, regardless of what it is," said Deacon Gary Wattie of St. Paul's Baptist Church in West Chester.

But Reggie Shuford, executive director of the American Civil Liberties Union of Pennsylvania, said that while the district attorneys offered "commonsense approaches," they could "go further than these guidelines to build public trust."

In a statement, Shuford said "transparency is completely undermined" when officers are named only if charged with a crime. He also said investigations into police-involved shootings should be handed over to outside prosecutors, because district attorneys work regularly with local police officers.

"While a local prosecutor can act fairly and objectively, the appearance is that he is investigating his friends," Shuford said.

Montgomery County District Attorney Kevin R. Steele, a member of the committee that developed the guidelines, said it used counties' current policies, and talked with community leaders and law enforcement officials.

Steele said bringing in an independent agency is critical to investigating police-involved shootings. His office has a policy of bringing in county detectives to investigate a shooting involving an officer from one of its municipalities.

"These situations are intense," Steele said. "They're situations that need to be looked at quickly and thoroughly, and I think these protocols give guidance to prosecutors and law enforcement agencies throughout the state."