The direction of the investigation came into sharper focus on Wednesday, when another friend of Tsarnaev's, Ibragim Todashev, was shot to death in Orlando, Fla., after allegedly trying to attack an FBI agent while he was being interrogated.
Two officials, speaking on condition of anonymity because they were not authorized to release details of the investigation, told The Associated Press that Todashev had implicated himself in the 2011 Waltham killings before he was shot.
The officials said they did not know if Todashev had also implicated Tsarnaev.
Nixon library hosts Vietnam POW reunion
Yorba Linda, Calif. • Two hundred Americans who were prisoners of war during the Vietnam conflict have arrived in California to mark the 40th anniversary of a White House dinner that celebrated their release.
The three-day gala started Thursday at the Richard Nixon Presidential Library & Museum in Yorba Linda. It will include a military flyover, wreath-laying ceremony and tours of a special exhibit on the prisoners' return home.
The reunion is centered around the anniversary of a special White House dinner hosted by President Nixon on May 23, 1973, to honor the 571 American POWs.
Nixon resigned a year later in the face of impeachment over Watergate, but many of the former POWs regard him as a hero for securing their freedom.
Maine governor moves out over a TV
Augusta, Maine • Maine's governor has temporarily moved out of his office at the State House and is working from the governor's mansion because of a dispute over a television.
Gov. Paul LePage is threatening to move for good by July 1. His move stems from a disagreement over a television screen in the hall outside his State House office. The screen notes the number of days since LePage introduced two legislative priorities that he wants lawmakers to act on. Legislative officials say no political messages are permitted outside State House offices.
The state Senate's Democratic leader calls LePage's move disappointing and frustrating. LePage, in turn, accuses Democrats of a pattern of toxic censorship.
LePage has drawn attention previously for telling the NAACP to "kiss my butt" and comparing the IRS to the Gestapo.
Mistrial declared in Arias penalty phase
Phoenix • Jurors who spent five months determining Jodi Arias' fate couldn't decide whether she should get life in prison or die for murdering her boyfriend, sending prosecutors back to the drawing board to rehash the shocking case of sex, lies and violence to another 12 people.
Judge Sherry Stephens gave a heavy sigh as she announced a mistrial in the penalty phase of the case Thursday and scheduled a July 18 retrial.
"This was not your typical trial," she told jurors. "You were asked to perform some very difficult duties."
The panel then filed out of the courtroom after 13 hours of deliberation that spanned three days, with one female juror turning to the victim's family and mouthing, "Sorry." She and two other women on the jury were crying.
None of the jurors commented as they left court.
The mistrial set the stage for a whole new proceeding to determine whether the 32-year-old former waitress should get a life sentence or the death penalty for murdering Travis Alexander five years ago. He was shot and stabbed nearly 30 times his throat slit ear to ear in what prosecutors said was a jealous rage because he wanted to date other people.
A new jury will be seated to try again to reach a decision on Arias' sentence unless the prosecutor takes execution off the table and agrees to a life term. Jury selection for the next phase could take weeks, given the difficulty of seating an impartial jury in a death penalty case that has attracted global attention.