NEW YORK - New York State Sen. Chuck Schumer is raising questions on exactly what the FBI knew about the Boston Marathon suspects prior to the bombings.

The Democrat spoke publicly saying, "I am a big defender of the FBI. I think they've done a great job on terrorism. But on this case, they may have messed up." He is also pushing for legislation to prevent any person on a terror watch list from legally buying a weapon.

The mother of the two suspects, brothers Dzhokhar and Tamerlan Tsarnaev, is meanwhile insisting that her sons are innocent and that she isn't a terrorist.

Zubeidat Tsarnaeva is drawing increased attention after federal officials say several of her phone calls were intercepted by Russian authorities. In one of those calls, she's accused of vaguely discussing Jihad with her oldest son in 2011. She was interviewed by the FBI that year as part of its investigation of Tamerlan, who was killed during a shootout with police last Friday.

Special tributes to the victims continue amid the ongoing investigation. The Old South Church, which is less than a block from the finish line, held its first Sunday service since the attack. It included a moment of silence and three bell rings for the three people who lost their lives.