Updated

A woman whose mother was killed in last year's school shooting in Newtown, Conn., confronted Sen. Kelly Ayotte Tuesday during the senator's first public appearance in New Hampshire since voting against gun control legislation.

About 150 people attended the town hall meeting, where Ayotte defended her vote against a bill that would have required criminal and mental health background checks for people buying guns online or at gun shows.

After the vote two weeks ago, the New Hampshire Republican, a former prosecutor, expressed concern that expanded background checks could harm the rights of gun owners.

"I'm just wondering why the burden of my mother being gunned down in the halls of her elementary school isn't as important," WMUR-TV reported Erica Lafferty asking.

Lafferty's mother, Dawn Hochsprung, was the principal of Sandy Hook Elementary School, where 20 pupils and six educators were slain in December. She died after lunging at the gunman to try to stop him from firing.

Ayotte said she was sorry for what Lafferty has been through.

"And I think that ultimately when we look at what happened in Sandy Hook we should have a fuller discussion to make sure that doesn't happen again," she said.

Ayotte said she hoped to find some common ground but that she didn't think the enhanced background checks that she voted against would have changed the outcome in the Newtown shootings.

"Mental health is the one area that I hope we can agree on going forward to work on because that seems to be the overriding issue on the list and that is why I have been trying to work across the aisle on that issue," she said.

Local and out-of-state groups who opposed Ayotte's vote held up signs that read "Shame on You." Ayotte supporters countered with signs reading "I support Kelly."