(CBS News) A former high school classmate of Tamerlan Tsarnaev -- the elder brother who was killed in a gun battle with police in the pre-dawn hours on Friday -- described the Boston Marathon bombing suspect in high school as "a very friendly guy, a funny guy -- almost a (comedian) Yakov Smirnoff-type personality."
Guive Rosen attended Cambridge Rindge and Latin School, a public high school located in Cambridge, Mass. Tamerlan Tsarnaev graduated a year before Rosen.
Rosen met Tsarnaev in his sophomore year and said he attended three classes with Tsarnaev.
"He was a boxer," Rosen said. "He was a very fun-loving person, comical, very friendly -- almost aggressively friendly, very friendly person. So it was very shocking to me when I saw his name on the news yesterday that he was the one that was the prime suspect for this."
Rosen described the moments after hearing Tsarnaev's name on the news: "It's a very unique name. Immediately I recognized it, but I thought, this can't be the same kid. I texted (a friend from high school) and said, 'Is this the same person that was in the class with us?' and it turned out to be and we said the same things -- everything that's being said on news, 'He was a gentle kid,' 'a nice kid,' 'it can't be him.'
"But it turned out to be him," Rosen said. "You know, I'm not sure how well other kids knew him in high school, but we were in class with him every day on a daily basis. So I talked to them and we shared the same emotions."
However, reports indicate that Tsarnaev had changed within the last two years, becoming more religious and reserved. Rosen said he had "zero contact" with Tsarnaev after he graduated in 2006.
"He did tell me while in high school that he was undefeated in the United States (in boxing). He said, you know, boxing in Russia was so much more difficult than in the United States. He was undefeated in the United States. But I have had no contact with him ...since he graduated, so I can't speak to the last year."
Tamerlan Tsarnaev's brother, Dzhokhar Tsarnaev, 19, is currently being treated at Beth Israel Deaconness Medical Center in Boston for gunshot wounds. He was in serious condition when he was apprehended, with gunshot wounds to his leg and neck, CBS News senior correspondent John Miller reports. He had been hiding in a boat in Watertown, Mass.