The Facebook account used a state trooper and has stirred concern that the Islamic State group may be trying to gather intelligence on US law enforcement. Pictured: Social networking site Facebook is displayed on a laptop screen, March 25, 2009. Dan Kitwood/Getty Images

An impostor Facebook account that used a retired Colorado state trooper’s identity has stirred concern that sympathizers of the Islamic State may be trying to gather intelligence on U.S. law enforcement, NBC News reported Friday. The unknown user friended both real police officers and apparent sympathizers of the Syria-based militant group, also known as ISIS, prompting a warning to officers to remain careful about whom they allow into “their digital community.”

"[We assess] with high confidence that it was designed under false pretenses to gather information regarding law enforcement members," read an internal bulletin from Colorado Information Analysis Center, a division of Colorado’s Department of Public Safety, according to NBC.

"Luckily, we caught it [the fake account] very early, but it's scary," Capt. J.P. Burt, director of the division, told NBC.

The Facebook account, which was shut down a day after it was created, had friends that authorities said appeared to espouse radical Islamic ideology and anti-Semitic beliefs. They also shared pictures of beheadings and killings. The state trooper whose identity was compromised was reportedly unaware of the account's existence, according to authorities who informed him of the situation Oct. 12, a day after the account was created.

ISIS has been known to spread its ideology through internet social media, and has in the past used Twitter and Facebook for recruitment. But a senior U.S. intelligence official said the group has not been known to use the “Facebook Phishing” tactic that has previously been used by other terrorist groups.

"International terrorist organizations and criminal domestic groups continue to violently target law enforcement and military members in the United States," the bulletin said. "They seek to exploit their personal information on social media."

The FBI would not comment on the Facebook page. It also did not mention whether the fake user was in U.S. or internationally based. More than 200 Americans have tried to join Islamic extremists in Iraq and Syria, the head of the FBI revealed in July. The figure is relatively low compared to other Western nations.