'I lost a piece of my heart,' says mom of 10-year-old shot dead along with his classmates, educators when gunman barricaded himself in 4th grade classroom at Robb Elementary School

Pro-gun lobby holds annual conference hours from scene of massacre earlier this week; attendees decry killing, but oppose weapons control

State public safety director says cops should have immediately breached room where shooter holed up with dead and wounded children, amid growing outrage over police inaction

Former US president tells pro-gun lobby that events like the 'evil' slaughter of 21 people in elementary school are 'one of the very best reasons' to arm citizens

Children frantically called 911 from dead teacher's phone while nearly 20 officers stood outside the classroom for 45 minutes waiting for someone to unlock the door

Joe Garcia passes away 'due to grief' just two days after his wife Irma Garcia was murdered while trying to protect her students

Anger and questions mount over slow police response and inaction as they waited outside while the gunman killed children, even preventing parents from trying to get in

Democrats envisioned measure rushed through House after Buffalo mass shooting as basis for negotiations on legislation targeting hate crimes and access to firearms

Parent whose daughter was killed says he wanted to run into elementary himself while police stood outside, amid questions over 40 minutes it took to enter classroom, shoot killer

'He kept to himself; he didn't have many friends,' Adriana Reyes says of her son, rejecting reports of a violent history; Biden urges new limitations on guns