A fire inside the old AC Delco plant off of Lyell Avenue Monday night is just the most recent in a string of fires at the former plant.

Rochester firefighters responded yet again to a fire at the former AC Delco plant off Lyell Avenue Monday night.

This fire follows one in February and is the latest in a string of fires at the old plant over the years. Firefighters were called around 11:30 p.m.

When crews arrived, they found heavy black smoke coming from the 4th and 5th floor windows. Firefighters used an exterior attack to knock down the flames in about a half-hour.

Battalion chief, John Kearney called this fire, like others at the plant, suspicious.

"Again there was no electricity to the building, there's no access to the building again then, it was the middle of winter, with snow flying and when you look at all of the windows that are open on this building, all of them are pretty suspicious when it's locked up like that and we have a fire of that volume in the building," said Kearney.

Crews went inside later to make sure no one was in the building. No one was hurt and the cause of the fire is under investigation.