LANCASTER, S.C. -- Just days after a fire destroyed a historic courthouse in Lancaster, officials are investigating a second arson that ravaged the nearby prosecutor's office.

Bureau of Alcohol, Tobacco and Firearms supervisor Randy Biggs said the fire in the one-story brick building began around 4:30 a.m. Thursday. The fire also damaged other offices.

No injuries were reported.

The Lancaster County Courthouse, that was built in 1828, suffered heavy damage in a fire Monday. No arrests have been made, and officials aren't saying if the two fires are connected.

The fire at the Lancaster County courthouse started at about 5 a.m. on Monday.

Police said that it appears some broke in through a courthouse window, set the fire on the second floor and then escaped through a back door.

The fire caused the roof of the building to collapse.

The courthouse was designed by Robert Mills, who also designed the Washington Monument.

Police Chief Hugh White said officers have been patrolling the area since Monday's fire and had been near the solicitor's office 15 minutes before Thursday's fire started.