PHILADELPHIA (CBSNewYork/AP) — Philadelphia’s police commissioner says a man who shot and killed a woman and wounded five other people, including two police officers, committed “one of the most violent acts that we’ve seen in Philadelphia in a long time.”

“Last night was a particularly violent night,” Commissioner Richard Ross said.

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Ross said 25-year-old Nicholas Glenn left behind a letter labeled “Doomed” that was full of “rantings” mostly about himself but also about his anger at his parole officer and police in general.

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He said Glenn was well-known to police and they believe he acted alone and not as part of any group. Ross said he “would have no difficulty” believing that mental illness was involved in Glenn’s actions.

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Authorities are working to track the weapon, which had an obliterated serial number.

Officials said Glenn walked up to Sgt. Sylvia Young as she sat in her patrol car and fired 18 times, striking her vest, her arm and disabling her service weapon.

He then fired into a bar, injuring a security guard, wounded a woman, and fired into a car, hitting a man and woman. That woman died just before 2 a.m. Saturday.

The suspect also wounded a University of Pennsylvania police officer before police killed him in an alley.

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