Investigators believe they know who intentionally set a series of fires in different areas of Waterloo early Thursday morning (June 29, 2017).

Justin Silos, 37, of Waterloo, is accused of torching five structures, all within a two-hour time span. He is charged with five counts of second-degree arson and public intoxication. Silos was found in the vicinity of the fifth fire and was taken to the Black Hawk County jail after being arrested.

"We feel (the fires) were the work of one person," Waterloo Fire Chief Pat Treloar said at a late morning news conference that also featured Police Chief Dan Trelka and Mayor Quentin Hart. "We're pretty sure Waterloo P.D. (police) has that person in custody."

Treloar said 28 firefighters and EMS personnel were on-duty at the city's six fire stations combined when the calls came in.

"Overall, we had all of our units -- six engines, three ambulances, our ladder truck and command vehicle -- out trying to mitigate these fires all at once," Treloar said. "During the time these fires were going on, we also responded to two serious 911 EMS calls that were unrelated to the fires. We were fortunate to be fully staffed."

Pat Treloar / Photo By: Elwin Huffman - Townsquare Media

The first fire at 2:50 a.m. destroyed a vacant home at 217 W. 8th St. Treloar said the two-story house (pictured above) was completely engulfed when firefighters arrived, so crews worked to protect two other nearby buildings that were in danger of catching on fire.

While firefighters were battling the blaze at 8th and Jefferson streets, crews were called to put out a second fire at 54 Lane St. around 3:22 a.m. Treloar described the fire as small. He said the blaze, located outside the former Altstadt and Langlas Bakery building, was quickly extinguished and caused minimal damage.

The third fire was reported approximately 20 minutes later at 121 Irving St., about four blocks from the second blaze. Treloar said firefighters doused a blaze on the front porch of the abandoned home.

At 4:07 a.m., the fourth fire was reported at 526 Logan Ave. The fire chief said that the blaze was "really rolling" when crews arrived at the scene, with flames shooting out of the vacant home's doors and windows. The fire was brought under control about an hour later.

Another residential fire was called in to dispatch at 4:21 a.m. at 521 Pine St. Treloar said it was a small fire, located inside the window well of a large, two-story building.

At the news conference, Trelka said an off-duty police officer on his way home saw the fire at 526 Logan Ave. and reported it. Moments later, the officer observed a man -- later identified as Silos -- walking on E. 4th St. and detained him. Trelka said Silos confessed to starting all five fires while being questioned by police.

"All in all, we were pretty lucky," Treloar said. "We had no injuries to our firefighters and no civilians were injured.

Each of the fires remain under investigation.