The threatening video, since taken down from YouTube, featured masks, eerie music and computerized voices. A group claiming to be the global hackers known as Anonymous said it posted the video, which threatens the department and an officer who arrested a Caledonia man outside a Green Bay bar last month.
The arrest video taken by a bystander shows the officer tackling and punching the man.
WISN-TV reports the FBI is investigating the threat. It's similar to one Albuquerque, N.M., police received last month which warned of a cyberattack on city websites. Albuquerque police said their website had been breached, but was back online the same day.