Green Bay, Wis. ? Police have arrested a third person in a foiled Columbine-style plan to bomb and shoot students at a high school, investigators said Saturday.

Two 17-year-olds were arrested Thursday at East High School after a student went to an associate principal. A detective said Friday that one boy wanted to enact the plan Thursday but that the other talked him out of it.

Bradley P. Netwal, 18, was arrested Friday on suspicion of conspiracy to commit homicide and conspiracy to commit arson, according to a police department news release Saturday.

Police learned from interviews that Netwal, a former student at the school and a friend of the 17-year-olds, participated in the planning, police said.

William C. Cornell and Shawn R. Sturtz were arrested Thursday on suspicion of conspiracy to commit first-degree intentional homicide and conspiracy to commit arson.