AURORA (Colorado), July 21: Police on Saturday de-activated a tripwire and triggered a controlled blast in the booby-trapped apartment of the gunman accused of killing 12 people at a Batman film premiere.

Bomb experts were inching their way into the home of James Holmes, the 24-year-old who allegedly opened fire on a packed midnight screening of ‘The Dark Knight Rises’, also injuring 58 others.

Police said they were confident they had eliminated ‘all major threats’ inside the third-floor apartment, a few miles away from the theatre where the massacre occurred early on Friday in Aurora, Colorado.

The horrific attack has revived the debate over gun control in the United States, and drew condemnation by President Barack Obama and his Republican White House rival Mitt Romney.

A small boom could be heard by reporters outside the apartment block and pieces of debris were blown out of one of the windows through which police have been assessing the booby trap inside. Five apartment blocks, including the one where Holmes lived, were evacuated shortly after he allegedly opened fire in a crowded theatre showing of the third instalment of the blockbuster ‘Dark Knight’ movie trilogy.

Police announced shortly before the controlled explosion that they had de-activated a tripwire. “This tripwire was set up to clearly detonate when somebody entered that apartment. It was set up to kill that person. That could have been a police officer executing a search warrant,” said police spokeswoman Cassidee Carlson.

Aurora police chief Dan Oates earlier described the apartment, seen via footage taken by a robot: “I see an awful lot of wires, trip wires, jars full of ammunition, jars full of liquid. Some things that look like mortar rounds.”—AFP