Three days before the Boston Marathon bombings , suspects Tamerlan and Dzhokhar Tsarnaev were working out together at a Boston gym . Security cameras captured footage of the brothers arriving at the Wai Kru mixed martial arts center with a friend just before 2:45 p.m. April 12 . The manager at Wai Kru , who wanted to be identified only as Michael , noticed a distinct change in the older brother 's appearance . Tamerlan Tsarnaev 's full , bushy religious beard , which he had for about two years , was gone . Michael described the older brother as extremely opinionated and outspoken about his Muslim religion . He said he did n't ask Tamerlan why he had shaved because he did n't want to engage in what was likely to be a long , heated debate . Now , Michael wonders whether Tamerlan 's shaving of his beard may have been part of an Islamic purification ritual prior to death . `` Shaving the beard may be a way to blend in , not to attract scrutiny from security services in carrying out the Boston attacks , '' CNN terror analyst Paul Cruickshank said . Tamerlan Tsarnaev trained at Wai Kru several times a month , for free , as a professional courtesy to the nationally ranked Golden Gloves boxer . His younger brother Dzhokhar rarely came , showing up just `` two or three times '' in roughly two years , Michael said . `` We 've seen with Western militants , wanna-be jihadists , a real emphasis on physical training , physical fitness , wanting to be prepared for jihad , '' Cruickshank said . In surveillance video recorded at Wai Kru and obtained by CNN , the manager -- who was off-camera -- asked the brothers to take off their shoes , as stated on the gym 's posted rules . Suspect : Boston bombing was payback for hits on Muslims . Dzhokhar Tsarnaev , 19 , complies right away . Tamerlan Tsarnaev , 26 , refuses to take off his shoes and argues instead . The manager later e-mailed the owner asking him to ban Tamerlan Tsarnaev , saying he 's arrogant , selfish and never helps anyone else . But the argument at the the gym that day did n't seem to faze Tamerlan Tsarnaev , who was the first to enter the ring . His years of training were evident as he skillfully handled the jump rope . His younger brother seemed to have more difficulty and less stamina as he struggled to hold up his oversized shorts . Another man who was with the brothers was introduced as a friend , the manager said . He was later questioned and released by the FBI . The brothers seemed relaxed at the gym -- though Dzhokhar rested at times and Tamerlan kept moving . Almost exactly 72 hours later , the bombs exploded near the finish line of the Boston Marathon . In the chaotic days that followed , Tamerlan Tsarnaev was killed in a police shootout , and his younger brother was captured after hiding in a boat in nearby Watertown , Massachusetts . FBI agents have seen the security footage from Wai Kru but were in a rush and took only a few screen grabs for still photos . The manager said he notified investigators about another Chechen -- Ibragim Todashev , a friend of Tamerlan Tsarnaev 's who also worked out at the gym . Todashev was shot and killed last week by an FBI agent . He was being questioned about a triple homicide on September 11 , 2011 . One of the victims from that triple homicide used to spar with Tamerlan -- at the Wai Kru gym .
The manager noticed Tamerlan Tsarnaev suddenly lost the full beard he had for years . `` Shaving the beard may be a way to blend in , '' a CNN terror analyst says . The manager says Tsarnaev 's friend also worked out at the gym . Todashev was killed last week while being questioned over a 2011 triple homicide .