US

Authorities taking extraordinary security measures for Boston Marathon bombing trial

  • Police stand guard behind television microphones set up outside the federal courthouse in Boston,Tuesday, Jan. 6, 2015, on the second day of jury selection in the trial of Boston Marathon bombing suspect Dzhokhar Tsarnaev. Tsarnaev is charged with the April 2013 attack that killed three people and injured more than 260. His trial is scheduled to begin on Jan. 26. He could face the death penalty if convicted. (AP Photo/Michael Dwyer)

    Police stand guard behind television microphones set up outside the federal courthouse in Boston,Tuesday, Jan. 6, 2015, on the second day of jury selection in the trial of Boston Marathon bombing suspect Dzhokhar Tsarnaev. Tsarnaev is charged with the April 2013 attack that killed three people and injured more than 260. His trial is scheduled to begin on Jan. 26. He could face the death penalty if convicted. (AP Photo/Michael Dwyer)  (The Associated Press)

  • Members of the legal defense team for Boston Marathon bombing suspect Dzhokhar Tsarnaev, Judy Clarke, foreground left, and Timothy Watkins, center, arrive back at the federal courthouse in Boston after the morning break, Tuesday, Jan. 6, 2015, on the second day of jury selection in Tsarnaev's trial. (AP Photo/Michael Dwyer)

    Members of the legal defense team for Boston Marathon bombing suspect Dzhokhar Tsarnaev, Judy Clarke, foreground left, and Timothy Watkins, center, arrive back at the federal courthouse in Boston after the morning break, Tuesday, Jan. 6, 2015, on the second day of jury selection in Tsarnaev's trial. (AP Photo/Michael Dwyer)  (The Associated Press)

  • Assistant U.S. Attorney Aloke Chakravarty, left, who is on the team prosecuting Boston Marathon bombing suspect Dzhokhar Tsarnaev, arrives back at the federal courthouse in Boston after a break, Tuesday, Jan. 6, 2015, on the second day of jury selection in Tsarnaev's trial. (AP Photo/Michael Dwyer)

    Assistant U.S. Attorney Aloke Chakravarty, left, who is on the team prosecuting Boston Marathon bombing suspect Dzhokhar Tsarnaev, arrives back at the federal courthouse in Boston after a break, Tuesday, Jan. 6, 2015, on the second day of jury selection in Tsarnaev's trial. (AP Photo/Michael Dwyer)  (The Associated Press)

Authorities have been taking extraordinary security measures since jury selection began in the trial of Boston Marathon bombing suspect Dzhokhar Tsarnaev (joh-HAHR' tsahr-NEYE'-ehv).

Homeland Security and Boston police are patrolling outside the federal courthouse in Boston. Armed U.S. Coast Guard boats are cruising the adjacent harbor, and officers with dogs are roaming the courtroom hallways.

The U.S. Marshals Service, charged with overseeing courthouse security, declined to comment this week on preparations.

Rick Avery of Securitas, a private security company not involved in the trial security, says he expects law enforcement to deploy bomb squads, snipers, undercover officers, enhanced surveillance operations and other measures for the duration of the trial.

Boston police say they're not aware of any credible threats.