Dzhokhar Tsarnaev. (Photo provided by FBI via Getty Images)
(CNN) - Some people who went to school with the second Boston Marathon bombing suspect said they are in shock by the news.
Eric Mercado said he went to high school with Dzhokhar Tsarnaev, 19.
A heavy police presence was going door-to-door searching for Dzhokhar in Watertown, Massachusetts.
"He was good friends with a bunch of us," said Mercado. "I know he worked at Harvard University as a lifeguard just recently. I don't know if he's still there. Yeah, we hung out, we partied, we were good high school friends. And a bunch all of my high school everybody, we're all like in shock. We don't understand. There was no telltale signs of any kind of malicious behavior from Dzhokhar. It's coming as a shock really."
Dzhokhar's brother was killed by police earlier Friday after a high-speed chase. He was identified as Tamerlan Tsarnaev, 26.
The suspects are originally from the Russian caucasus and moved to the United States several years ago.