It is unclear what Boston bombing suspect Tamerlan Tsarnaev’s activities were in a six-month trip overseas taken in 2012 where he visited Russia. His parents have insisted his visit to Dagestan and Chechnya last year was to see relatives and had nothing to do with the militants operating in this region of Russia.

But a report from CNN on such militants has a police chief alleging one such extremist ran bomb-making training camps and met with foreigners, including a group from Chechnya, raising the possibility that Tamerlan could have been in that group.

CNN reported a video posted by Tsarnaev, which was later removed shows, militant Abu Dujan, a jihadist in Dagestan who was killed by Russian troops in December 2012. It is unknown if Tsarnaev, who was killed in a police shootout last Thursday, ever met with Dujan.

Dagestani Militant Abu Dujan Taught Others How to Make Bombs

Abu Dujan pictured in a YouTube video. (Image: CNN screenshot)

“They met to exchange their bandit experience,” Police Chief Askhabali Saurbekov of Kizilyurt told CNN of a group meeting with Dujan before his death. Askhabali could not disclose how many were in the group of foreigners that met with Dujan and said he didn’t know if Americans were among them, although it was possible.

Tsarnaev, along with his brother Dzhokhar Tsarnaev, is a suspect in twin bombings near the finish line of the Boston Marathon April 15, which killed three and injured hundreds. The type of IED detonated based on evidence found was said to be a pressure-cooker bomb. In the days that followed the bombing, the FBI identified the 26-year-old and 19-year-old brothers and tracked them down. Tsarnaev was killed in a police shootout April 18 and his brother was captured hiding in a boat in the backyard of a Watertown, Massachusetts, home April 19. Dzhokhar Tsarnaev was taken to a hospital and is in custody.

The Dagestani police told CNN that Dujan taught others how to make bombs, including mixing of explosives and using cellphones as detonators.

CNN’s reporter says in the video that there are reports Dujan was observed meeting Tsarnaev at a local mosque. The reporter asks Askhabali if he knew about such a meeting.

“I really can’t answer this. For different reasons, I can’t answer,” the police chief said.

Watch CNN’s report: