MADISON, Wis. -

Madison police detectives are continuing to investigate the materials found in a downtown Madison residence Saturday.

Officials said MPD has concerns about some of the materials seized from a residence on the 10 block of North Brooks Street just after 2 p.m. on Saturday.

Police have requested help from the FBI, the Dane County Sheriff’s Office Bomb Squad and the Wisconsin National Guard 54th Civil Support Team, according to a release.

On Saturday, officers found items and documents indicating the manufacturing of an explosive device. Police arrested 20-year-old Andrew T. Cockerham on suspicion of possession of an explosive device.

Cockerham has told investigators that he is involved in amateur design, constructing and launching of rockets, and that chemistry is one of his hobbies.

University of Wisconsin officials said Cockerham is a former student who studied chemical engineering.

Detectives are working to determine if there are other reasons why Cockerham would possess some of the materials that were seized.

Madison crime stories from the past 12 months - locations are approximate