The FBI says Orlando shooter Omar Mateen made a reference to the Boston Marathon bombers in a 911 call he made during the attack, calling them his "homeboys."
The reference to Tamerlan and Dzhokhar Tsarnaev came during one of the calls between Mateen and a 911 operator, according to the FBI.
Despite the reference, FBI Special Agent in Charge Harold Shaw and other authorities have said the investigation has not uncovered any evidence of a relationship between the Tsarnaevs and Mateen.
"At this point in time, all evidence collected to date shows no connection between Mateen and the Tsarnaev brothers," Shaw said in a statement.
The FBI also said there are "no specific, credible threats" to the Boston area as a result of the Orlando attack.
Massachusetts State Police first confirmed on Sunday that Mateen had pledged allegiance to ISIS and referenced the Tsarnaev brothers during his rampage.
Mateen killed 49 people and injured 53 others in the shooting at Pulse night club early Sunday morning. The incident is now the deadliest mass shooting in United States history.
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In the wake of the connection to the Boston bombings, the Commonwealth Fusion Center is sharing information with federal authorities investigating the Orlando terrorist act as well as with police assigned to the Boston Regional Intelligence Center. State police said Mateen did not appear in any local databases of potential terror suspects.
Massachusetts Gov. Charlie Baker said Monday there is "no direct connection" between Mateen and the Tsarnaev brothers.
"At this time, there's no reason to believe there's much to that," he said.
Baker said from what he's been told, federal officials spoke with Mateen years ago after he referenced the Tsarnaev brothers but did not determine him to pose a serious threat.
"We do know that he raised the Tsarnaev brothers a couple of years ago, and there were a series of interviews and discussions directly with him by federal officials, and they concluded at that point in time that there was no direction between him and them at all," the governor said.
Baker did not elaborate. He said he was relaying information Massachusetts officials received during a briefing by federal officials investigating the Orlando shooting.
The Tsarnaevs planted two pressure-cooker bombs near the finish line of the marathon on April 15, 2013, killing three people and injuring more than 260.
Tamerlan Tsarnaev, 26, was killed during a getaway attempt several days after the bombings. Dzhokhar, then 19, was sentenced to death last year for his role in the bombings.
During Dzhokhar Tsarnaev's trial, his lawyers argued Dzhokhar had been heavily influenced by Tamerlan, a former boxer who embraced radical Islam and masterminded the bombings. Prosecutors said the Tsarnaevs, Muslims who lived in the Soviet republic of Kyrgyzstan and Russia before coming to the United States as children, became radicalized in part by reading online extremist materials, including Inspire, an al-Qaida magazine.
Mateen, the son of an Afghan immigrant, had "strong indications of radicalization" and was likely inspired by foreign terrorist organizations, FBI Director James Comey said. Authorities said Mateen had twice come to the FBI's attention. Once was by co-workers who expressed concern over statements he'd made about possible ties to terrorist groups, sparking a 10-month investigation.