An investigation continues into whether the shooting of a Philadelphia police officer is part of a larger plot to target law enforcement.

FOX's Tonya J. Powers has the story:

Philadelphia police and the FBI are looking into a tip that the self-proclaimed ISIS-inspired shooter who attacked officer Jesse Hartnett may be part of a larger group that's targeting officers.

The Philadelphia Inquirer reports a woman told police that Edward Archer had associations with three other men, all of whom were more radical than Archer.

Archer is charged with aggravated assault, assault of a law enforcement officer, and several firearms crimes and is being held without bail.

He is accused of firing more than a dozen shots into the officer's car last Thursday, hitting him three times.

Archer later confessed to the attack, saying he pledged allegiance to ISIS.

Tonya J. Powers, FOX News.