A gunman who wounded two Philadelphia police officers and three civilians and killed a fourth civilian appears to have opened fire because he was driven by hatred for the police, officials said on Saturday.
Police did not immediately identify the gunman who they said began a shooting spree late on Friday and later was killed by responding officers.
Sergeant Sylvia Young, a 19-year veteran of the Philadelphia Police Department, was shot at least eight times by the gunman as she sat in her vehicle late at night, Police Commissioner Richard Ross said.
"He just walks up on her ... He just fired. He didn't say anything," Ross told a news conference on Saturday, saying the suspect fired about 15 rounds into Young's vehicle.
Police found a "rambling" letter allegedly written by the gunman in which he expressed hatred toward police and probation officers, Ross said, according to the Philadelphia Inquirer. He said there was no reason to believe at this point that the gunman had any religious beliefs that drove him to the shootings, the newspaper reported.
Philadelphia police could not be reached immediately to confirm the reports of a letter or its contents.
The gunman was "driven by hatred," police spokesman John Stanford said on Twitter.