Fire investigators are trying to determine what sparked a fire that heavily damaged a vacant house in northwest Atlanta.

Electricity and gas to the house on Thurmond Street had been disconnected, leading authorities to suspect that vagrants set the fire, which broke out around 9 a.m. Friday.

“Even though it’s considered a vacant house, we know that we have a lot of vagrant activity in this area,” Atlanta fire Battalion Chief Todd Edwards to the Atlanta Journal-Constitution. “We had companies search out the entire building; fortunately, everyone had gotten out of the house.”

Edwards said that recent staffing increases made his crew’s job easier Friday.

“We received a grant from the federal government that allowed us to do a lot more hiring, and with the budget increases over the last couple of years, we’ve been able to bring our staffing level back up to where it’s supposed to be for a safe operating level,” Edwards said.

“Instead of having three guys on the rigs, now we’re putting four to five guys on all our apparatus, and that’s given us such an advantage,” Edwards said. “Now we’ve got the personnel to handle any size fire we respond to.”