The deadly apartment explosion that left one person dead in Beaver Dam is just the latest case of explosive devices being inside a private residence in southern Wisconsin in two weeks. It begs the question: where are the chemicals and other ingredients coming from?
First, bomb ingredients were found inside a west Madison apartment building at the end of February.
Then, an explosion went off this week at an apartment in Beaver Dam.
But explosives being found in residences isn't as rare as you think.
According to the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), 859 explosives investigations were opened in 2014 alone.
Law enforcement agencies, including those investigating the Beaver Dam explosion say explosion devices are getting easier to make.
"Unfortunately you can make explosives in a variety of different manners with household chemicals. I can't speak directly to that situation, but yes, that is the case in a number of incidents and we're seeing what those materials were and how they were obtained," said Justin Tolomeo, the FBI Special Agent in charge.
Those noted household items and materials that could create a bomb were found inside the west Madison apartment two weeks ago.
According to a criminal complaint, Brian Campbell had ingredients like Vaseline, coffee filters and antifreeze -- which mixed with other dangerous chemicals could create an explosive device.
Investigators are still trying to determine exactly what type of chemicals were found in the Beaver Dam apartment.