FREDERICK, Md. (AP) — Officials are investigating fires at three homes they say were intentionally set.

WJLA-TV reports that Frederick County fire officials have determined that three separate fires discovered on Feb. 5 and 6 were caused by acts of arson.

The Frederick County Sheriff’s Office says fire crews were called to a townhome under construction at about 2 a.m. on Feb. 5, and were able to put out a small blaze that was started with construction materials. Construction crews found the remains of a second fire that had caused damage to a townhome, also under construction but almost finished. Remains of a third fire were discovered the next day in another home under construction.

Investigators are looking into the fires and searching for suspects.