‘Lone Wolf’ Bomber Arrested in Upper Manhattan

Authorities have arrested a man who law enforcement officials believe was planning to build and detonate a bomb in New York with government workers, returning military personnel and elected officials as the target, a person briefed on the case said on Sunday.

Mayor Michael R. Bloomberg, Commissioner Raymond W. Kelly of the New York Police Department, and Manhattan District Attorney Cyrus R. Vance Jr. were expected to announce the charges against the man at 7:30 p.m. at a news conference at City Hall.

The man was arrested within the last 24 hours.

The defendant in the case, identified as Jose Pimentel, had bought bomb-making materials and “began to build them,” said the person briefed on the case, who added that the Police Department had had the man under surveillance for about a year.

The person briefed on the case described it as a “lone wolf scenario” and said that Mr. Pimentel had been considering a possible array of targets that included government employees, lawmakers and military personnel returning from overseas service.