An unsolved triple murder has been linked to one of the suspects in the 2013 Boston marathon bombing. A Hulu docuseries takes a deeper look at the investigation.

The three-part investigative series explores an unsolved triple-murder mystery that rocked a quiet Boston suburb in 2011 and its possible link to the infamous Boston Marathon bombing.

For Henry Richard, the brother of a Boston Marathon bombing victim, the journey to the finish line at this year's marathon was nearly a decade in the making. ABC News’ Will Ganss has his story.

The Supreme Court reinstated the death sentence for Boston Marathon bomber Dzhokhar Tsarnaev.

Reciting the gruesome details of the Boston Marathon bombing, a Justice Department lawyer asked the Supreme Court to reinstate the death sentence for Dzhokhar Tsarnaev.

The Justice Department is asking the Supreme Court to reinstate the death sentence for Boston Marathon bomber Dzhokhar Tsarnaev, despite a Biden moratorium.

"There was such a sigh of relief," Jacqui Webb said of seeing Casper after eight years. "Having Nichole again and having her understand my past, was extremely comforting."

Martin Richard was 8 years old when he was killed on April 15, 2013.

The park, next to the Boston Children's Museum, is expected to open in the fall of 2018.

The teen received microprocessor knees to help him get back on his feet.

Mark Wahlberg and Kevin Bacon star in the movie, which portrays the day's events and the subsequent manhunt for the bombers.

Just minutes after killing 3, Boston bombers went to the market.

Bogus information paralyzes Boston for hours before second bomber captured.

Watertown Police Sgt. Jeff Pugliese was less than three yards from the man shooting at him when his own pistol ran out of ammo.

FBI struggles to learn identity of the bombers, confusion over arrest abounds.

FBI agent recounts “ah-ha” moment when analysts spotted the bombers.

Wahlberg was dressed as a police officer.