TMJ4, our sister station in Milwaukee, is following an active police investigation in a Madison neighborhood on the citys north side.A neighbor, who spoke with TMJ4 off camera, said they heard flash bangs and saw police with long guns between 1 p.m. and 1:30 p.m.Its unclear if the investigation is related to the shooting at Abundant Life Christian School in Madison, which left three people dead, including the suspected shooter.RELATED: Read NBC 26's live updates on the shooting TMJ4 has spoken with the Madison Police Department on the scene of the investigation, but they have not provided any information.This is a developing story and will be updated both in this article, and our live update article.