Pokémon Go may have much of the country obsessed, but players need to be careful, because criminals are using the popular app to easily target victims and rob them. Police in O’Fallon, Missouri, say they are investigating a series of armed robberies in St. Louis and St. Charles counties in which players of the augmented reality game were the victims.

Police put out the warning on Facebook after they located four teenagers, who ranged in age from 16 to 18, inside a car with a handgun when they were answering a call about an armed robbery early Sunday morning. They say the suspects appeared to use the app to lure players to an isolated location and then rob them. Authorities believe the four teenagers had robbed around eight or nine people over the past few days.

“The way we believe it was used is you can add a beacon to a pokestop to lure more players. Apparently they were using the app to locate ppl standing around in the middle of a parking lot or whatever other location they were in,” according to a press release the O’Fallon, Missouri police department posted on Facebook.