ABC News reported this week that the FBI is working with other agencies to identify the culprits behind an online hit list of U.S. military personnel posted by ISIS. Investigators believe the list–containing names, photographs, and addresses — was gathered by trolling social media.

Former Homeland Security counterterrorism coordinator and ABC News contributor John COhen said the hit list serves as a stark reminder. “We have to place a much higher priority in this country in securing our key data, securing data particularly of those individuals who are responsible or involved in military operations or law enforcement operations.”

When it comes to social media Coheen said members of the military and law enforcement should think twice before posting. “The new frontier of intelligence collection is gaining information off the internet or off social media.”