Aurora police officers testified in court on Thursday that James Holmes helped diffuse explosives that he rigged at his apartment after committing the mass shooting in a crowded movie theater, which left 12 people killed and critically injured scores more on July 20, 2012, The Huffington Post reported.
Lt. Thomas Wilkes said explosives found at Holmes' apartment had been so sophisticated and difficult to diffuse that police considered letting the building burn down, believing that would be a safer alternative, The Denver Post reported.
"We knew that building would go. The idea was, 'can we defend the other buildings?", Wilkes told the court on Thursday. Instead, Wilkes explained that the police opted to interview Holmes about how to diffuse the explosives, and the gunman the told FBI agents how to do it step by step, much to their surprise, KDVR reported.
This questioning was done without an attorney present, an argument that Holmes' lawyers are using in hopes that it will be thrown it, saying it was a violation of his constitutional rights, news reports said.
"More than 30 homemade grenades, 10 gallons of gasoline, improvised explosive devices (IED's) and trip wires or trigger mechanisms were secured from the Aurora, Colorado home," CNN reported a week after the mass shooting.
The sophisticated setup at the "sparsely furnished third-floor, one-bedroom apartment of Holmeswas meant to harm, or possibly kill, anyone who entered - and tested the skills of bomb squad members charged with clearing it," CNN also reported.
"Imagine that fireball ... you would have an explosion that would knock down the wall of (nearby) apartments," an official said to CNN at the time."That flame would have consumed the entire third floor. By the time a fire truck would have arrived, they would have arrived to a building that would have been completely consumed in flames," he added.
Holmes has pleaded not guilty by reason of insanity to 166 counts of murder, attempted murder and other charges.
Prosecutors are seeking the death penalty, and must prove that Homes was legally sane at the time of the shooting.
