An Internet service that transmits police radio calls has cut off broadcasts from Boston-area police departments for fear of jeopardizing first responders during the Boston terrorist manhunt.

Tens of thousands of news junkies from around the world had been using the service to follow the story.

Broadcastify.com of San Antonio, Texas, works with a nationwide network of volunteers who connect police radios to their computers, then transmit the incoming calls to a central server. Law enforcement buffs and journalists can log in and listen on personal computers or through smartphone apps.