INDIANAPOLIS - Gunfire has struck an Indianapolis police department district office, and officials said Friday that investigators believe whoever is behind this attack also shot at another city police district office this month.

No one was injured in either shooting, the latest of which happened about 11 p.m. Thursday at the North District Headquarters.

"This person is extremely violent," Chief Troy Riggs of the Indianapolis Metropolitan Police Department told reporters early Friday. "It's someone that we need to be vigilant in trying to capture quickly."

During a news conference later Friday, Mayor Joe Hogsett, a former federal prosecutor, said those responsible for targeting the police will be arrested and held "fully accountable for these acts."

"Your senseless violence does not represent this community. Your senseless violence does not represent any group of people or gang or social movement. Your senseless violence represents one thing and one thing only, the acts of a coward who doesn't deserve the honour of living in a city that is the home of the brave men and women of IMPD," Hogsett said.

After the first shooting, Riggs had said it may have been in response to a recent crackdown on drugs that included arresting suspected drug dealers and taking more than $3 million in narcotics off the street. Department spokesman Sgt. Kendale Adams said Friday that remains a possible trigger, but with no one in custody related to the shootings it can't be stated definitively.

"We're looking at a lot of different angles, and that's one we're looking at," he said.

On Thursday night, police say officers inside the building heard shots and took cover before trying to find a suspect. Some windows and walls were damaged, and a vehicle in a parking lot was struck by gunfire. Witnesses reported hearing a vehicle speed away afterward.

Police didn't immediately confirm how many shots were fired, but Riggs said at last one bullet entered the building.

In a statement, the Indianapolis Metropolitan Police Department said that an initial investigation suggests the suspect or suspects who shot at the North District headquarters also was responsible for the shooting Oct. 4 at the Northwest District Headquarters.

In the first shooting, which also is under investigation, the building's front was struck by at least a dozen bullets and at least two windows were damaged.

News from © The Associated Press, 2016