Dallas firefighters are investigating three suspicious fires.
Dallas firefighters were busy overnight Wednesday battling four fires -- three in the same neighborhood.
The three adjacent fires were at vacant homes at 2715 Gertrude, 3610 Frank Street and 3900 Spring Avenue.
Just before 1 a.m., firefighters arrived at the vacant, one-story home on Frank Street and began battling the heavy flames. During the fight, another fire broke out a few blocks away on Gertrude Avenue.
When crews arrived at the vacant, one-story home on Gertrude Avenue, they also found heavy fire. While working that fire, they received a call of the fire on Spring Avenue.
For nearly five hours, Dallas firefighters battled the three fires. Given the proximity to each other, the fires at the vacant homes are being considered suspicious. Investigators are looking into whether or not they may be the work of an arsonist, though no determination has been made at this point.
The fourth fire, at 5100 Ash Lane, is not believed to be connected to the other three fires.
NBC 5's Amanda Fitzpatrick contributed to this report.