Federal officials are silent on why they raided homes in Bryan, Houston and Michigan that property records indicate are owned by a Houston couple.
FBI agents in Texas have finished their searches, but spokeswoman Shauna Dunlap said Monday she could not comment.
Sheriff Mike Borkovich in Leelanau County, Mich., says the FBI was still in the area Monday but would not discuss their activities.
Agents, some wearing hazardous materials protective clothing, searched a Woodland Court Condominium in Bryan and two Houston-area homes Friday. Agents also raided two properties in Michigan.
The FBI says agents Saturday touched off two detonations at a Houston home in the 400 block Fall River Road, but the FBI did not say what they were detonating.
"For the safety of the nearby public, the nearby residences and our law enforcement personnel, we needed to dispose of that substance in the backyard of that residence," said Dunlap.
News 3 attempted to locate the residents of the Bryan condo Monday; no one answered the door. However, neighbors said they noticed the home's garage had a warehouse type of set up and thought it was rather unusual.
Records show the homes are owned by art appraiser Cecily Horton or by Horton and her husband Andrew Schneck.
The couple did not return messages Monday.
While the Leelanau County Sheriff's office did not return our calls, according to its website, "the investigation is not related to any other sites or investigations in Michigan but other searches are being conducted related to the case in other states. It is unknown when the search and investigation here will end or whether anyone will be charged as a result."
No arrests have been made.