“We believe we’ve shut it down,” Mr. Carey said after the news conference, though he added that residents in New Jersey’s large Indian-American population should remain vigilant. He also said that the investigation, which involved state and federal authorities, was continuing and that more arrests could be made.

From Oct. 20 to Nov. 29, five Indian-American families, all living in middle-class or upper-income suburban homes in Old Bridge, Edison and South Plainfield, N.J., were attacked. The assailants burst through doors, waved and pointed guns, bound family members with duct tape, punched and kicked them, and took off with jewelry, cash and electronics, the authorities and the victims have said.

Mr. Carey said he believed the first four robberies were linked to Diwali, a festival that took place this year in late October. Gold is often worn during the celebration, and is prized inside homes during the religious holiday. One family in Edison reported being robbed of tens of thousands of dollars’ worth of necklaces, rings, earrings and pendants.

While some Indian-Americans in Middlesex County had complained about lack of communication from local authorities during the recent tension-filled weeks — openly wondering, for instance, why Mr. Carey had not released descriptions of the suspects — they seemed largely pleased on Monday.

“We are all very, very relieved that this episode has come to a conclusion,” said Satish Poondi, a legal adviser for New Jersey’s Indian Business Association.