Police Study Way to Jam Cellphones in an Attack

By AL BAKER

New York police officials are studying the feasibility of disrupting cellphone communications between terrorists during any attack, after revelations that gunmen in Mumbai received electronic transmissions during their killing spree in November.

Police Commissioner Raymond W. Kelly raised the possibility in Washington at a Senate hearing on Thursday, but he noted there were technological hurdles to shutting down cellular service in a narrow location, like a hotel or movie theater.

At the hearing of the Senate Committee on Homeland Security and Governmental Affairs, Mr. Kelly testified, “Law enforcement needs to find ways to disrupt cellphones and other communications” during an unfolding crisis like the one in Mumbai.

But he stressed, under questioning by senators, that care must be taken in pursuing such plans, suggesting that widespread shutdowns could hamper emergency personnel or keep civilians from making emergency calls.

Later, Paul J. Browne, the Police Department’s chief spokesman, said the department wanted to preserve the option of monitoring conversations between terrorists should that prove more advantageous than cutting them off. He said that any plan to shut electronics transmissions was “only in the discussion stage.”

Mr. Browne said, “Our communications and technology people are looking for ways to disrupt cellphone and hand-held devices in a pinpointed way.”

He added: “We are not at a point where we are testing any equipment. We are talking to the industry and to people in other government agencies and among ourselves. What is known about this? What is possible? And what is being tested along these lines?”

Electronic jamming of cellphones or of global positioning systems is complicated but possible, and might already be in use by foreign military agencies, said Eric Lustig, a data systems manager at Eastern Communications, a Queens company that provides radio equipment to government agencies and other clients.

Cellular service in a big region, like a borough, could be simply shut down, he said. More compact sites, like an official motorcade, could be jammed by devices in the cars.

“You cannot draw straight lines around, or a circle around, an area where you would do it, but it is certainly possible to jam an area,” Mr. Lustig said. “If you are talking about a tall building, you would knock out cellphone communications for a far larger area. If you just wanted to knock out cellphones in a movie theater, it could be done.”

Mr. Lustig said it would be much more difficult to jam a satellite phone than a cellular phone, since the antenna is pointed at the sky.

Eric Schmitt contributed reporting.