NEW DELHI — Indian police officers on Friday swooped down on neighborhoods in the capital that have been racked by religious violence this week, arresting more than a dozen people amid a brewing controversy over where to place blame for the bloodshed.

Lines of officers searched homes and combed through burned-out properties where some suspects were thought to be hiding as more residents, especially Muslims, fled the area.

So far, the authorities’ investigation has focused on opposition and Muslim leaders, including Tahir Hussain, a city councilor from a progressive political party. The police have put Mr. Hussain under investigation on suspicion of murder, saying they found a crate of Molotov cocktails on the roof of his house. Mr. Hussain has denied the accusations, calling them political persecution.

“I am innocent and ready to face any investigation,” Mr. Hussain said in an interview with an Indian television channel, adding that it was those responsible for setting fires who should be arrested.