Authorities executed search warrants and seized evidence early Monday morning at locations in the Queens borough of New York City as part of a terrorism investigation, according to a senior official familiar with the case.

This person said some counterterrorism officials were concerned that the individual at the center of the investigation may have had access to, or an interest in acquiring, materials that could be used for a chemical, biological or radiological device. One aspect of the probe involves whether the person had some contact or connections with suspicious individuals overseas, the official said. He stressed that the investigation was still at its earliest stages.