Proposed changes to the nation's immigration laws would have made it easier to track one of the suspects in the Boston Marathon bombings before the attack, the nation's homeland security chief said Tuesday.

Homeland Security Secretary Janet Napolitano also confirmed that federal agencies didn't  initially notice that one of the two suspected bombers, Tamerlan Tsarnaev, had left the country last year on a six-month trip to Russia because his name was misspelled on his airline ticket. Other unspecified "redundancies" eventually alerted federal agencies that Tsarnaev had left the country, she said.