BRISTOL, R.I. (AP) — Police in Bristol, Rhode Island said Tuesday they are investigating the discovery of several Nazi-themed stickers in town.

The investigation started Saturday when someone reported finding a sticker with an image of Adolf Hitler and the words “white boy summer” on a window at the town library, police said in a statement.

The person removed the sticker, and gave it to the police.

Later on the same day, someone else reported an identical sticker on a mailbox outside of the post office, according to police.

Officers checked the area and found four more stickers. They were removed and processed as evidence.

Police also released surveillance camera images of two possible suspects who they are still trying to identify and locate.

Police in neighboring Warren are investigating the posting of racist stickers last week, and the two departments are working together to determine whether the incidents are connected.

Bristol police have also contacted the civil rights unit of the Rhode Island Attorney General’s Office to review the case as a possible hate crime.