Philadelphia police have been told that three "radical" associates of a self-proclaimed ISIS-inspired gunman who attacked a cop Thursday were still at large and that "the threat to police is not over," according to a published report. 

A law enforcement source told Fox News that city police and the FBI were investigating the tip, which came from a woman who stopped an officer on the street Saturday night.

The Philadelpha Inquirer reported Sunday that the woman told police that Edward Archer, who allegedly shot and wounded Officer Jesse Hartnett while the officer sat in his patrol car, had associations with three other men, all of whom were more "radical" than Archer. 

 

The Inquirer, citing police sources, reported that the tipster warned that the three men all frequented an area near where Hartnett was shot and warned police to be careful.

"The Philadelphia Police Department has alerted all department personnel of this matter and will continue to have officers work with a partner until further notice," a statement from the department said.

Archer, 30, has been charged with attempted murder, aggravated assault, assault of a law enforcement officer and several firearms crimes. After his arrest, Archer allegedly told authorities he was "following Allah" and pledged allegiance to ISIS, and he believed the police department defends laws that are contrary to Islam.

Harnett was last reported in stable condition at the hospital after Archer allegedly charged the officer's car as he patrolled his usual west Philadelphia beat shortly before midnight Thursday, firing at least 13 shots, hitting the officer three times. Hartnett got out of his car, chased the man and returned fire, wounding him in the buttocks before he was captured by other officers about a block away.

Authorities believe Archer traveled to Saudi Arabia in 2011 and to Egypt in 2012 and are investigating the purpose of those trips. FBI special agent Eric Ruona said Sunday that as U.S. authorities work with partners overseas, it would take time to find any potential terror connections, and it was too early for any meaningful comment on the subject.

Archer's brother Shane told Fox 29 that the suspect was neither mentally ill, as suggested by his mother on Friday, nor was he connected to ISIS. Shane Archer says Edward did travel to Mecca but he believes the alleged shooting was more closely related to what he called police mistreatment of black men than religion.

However, the Inquirer reported that the tipster told police that Edward Archer "became more radical" after attending a mosque in the area. 

Earlier Saturday, police said a man tried to grab the gun of a Philadelphia officer working a detail at the hospital where Hartnett is recovering, but they believe the incident is unrelated to the ambush shooting.

Police said the man approached the officer outside Penn Presbyterian Medical Center shortly after 10:30 p.m. Saturday and asked for money, saying he hadn't eaten in five days. The officer handed the man a $5 bill and entered the medical center, but later, when he was standing near the emergency room exit doors, the man tried to grab the officer's handgun from the holster. The officer, with the aid of hospital security and other officers, subdued the 40-year-old suspect, who said he wanted the gun to rob a store, police said.

Police said the incident appeared unrelated to Hartnett's shooting, but was "an example of the type of individuals that our officers face daily when performing their duties as Philadelphia police officers."

A fundraising page has been set up to raise money to help pay the expenses of the wounded officer, who was shot three times in the arm and will require multiple surgeries. The GoFundMe page had recorded $17,530 on Sunday afternoon.

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The Associated Press contributed to this report.