Boston law enforcement indicated on the emergency personnel radio scanner at 3:53 p.m. ET that they would be conducting a controlled explosion on the 600 block of Boylston Street, near the Copley Square site of the original explosions that rocked the Boston Marathon earlier Monday afternoon. The explosion occurred around 3:55 p.m. ET.
Other updates from emergency personnel scanner since 3:30 p.m. ET:
- The incident command is set up at the Westin Hotel.
- "[Placing injured into ambulances] phase seems to be over."
- Personnel on the channel suspect the devices may have been placed in trash barrels. "All officers coming into the area are to be cautious of trash containers."
- Emergency personnel is trying to move a busload of runners at the Mass Avenue underpass.
- Outside incoming agencies will stage at Ring Road and Huntingdon.
- No cell phone use, as cell towers are overloaded.
- At 3:50, a call was placed for more explosive dogs and swat team members.
- At 3:52, armored trucks were en route.