CENTENNIAL — As the sun rose the morning of July 20, 2012, investigators outside the Aurora movie theater shooter’s apartment had a problem: The explosives inside the apartment appeared so complicated and so dangerous it was unclear whether they could even be defused.

Investigators believed their best option was to set off the bombs and let them burn the entire three-story complex down.

“We knew that building would go,” Aurora police Lt. Thomas Wilkes, the incident commander at the apartment, testified at a court hearing Thursday. “The idea was, ‘Can we defend the other buildings?'”

The solution authorities ultimately reached spared the apartment building, but it may now cause significant damage to the prosecution’s case against theater shooter James Holmes.

Investigators chose to interrogate Holmes about the explosives on the afternoon of July 20 without a defense attorney present. The decision was made despite Holmes requesting an attorney earlier in the day. And — in a new revelation Thursday — the interrogation came just three hours after an attorney hired by Holmes’ mother told police they were not permitted to speak with him.

Defense attorneys say the statements should be thrown out because Holmes was denied his right to an attorney. If that happens, prosecutors won’t be able to use the statements at trial to link Holmes to the bombs or — more significantly — to argue that Holmes was sane at the time of the shooting.

The interrogation about the explosives lasted 37 minutes and was the most lengthy conversation Holmes had with police in the hours after the shooting that killed 12 people and wounded dozens more.

“The important constitutional protections every American has are in place to avoid just such police conduct,” said Dan Recht, a Denver defense attorney and legal analyst. “… You just can’t deny someone the right to counsel for so long and interrogate him in the interim.”

Prosecutors argue the statements were properly obtained because of the urgent public-safety risk and should be allowed at trial. FBI special agent Garrett Gumbinner testified Thursday that talking to Holmes was the only way to figure out how to defuse the explosives.

“It made us smarter,” Gumbinner said.

Holmes is charged with 166 counts of murder, attempted murder and other offenses in the shootings. He has pleaded not guilty by reason of insanity.

Aurora detectives Craig Appel and Chuck Mehl first tried to interview Holmes at 2:44 a.m. on July 20 in an interrogation room at the Aurora police headquarters. Holmes asked the detectives for water and oxygen, according to the detectives’ testimony Thursday. He told the detectives he wanted an attorney about seven minutes into the interrogation, after Mehl read him his rights.

Denver defense attorney Iris Eytan testified that Holmes’ mother, Arlene, called around 10:30 a.m. on July 20 and hired Eytan to represent her son. Eytan said she received a call around noon from Appel, who asked whether investigators could talk to Holmes about the explosives in order to defuse them safely.

“He said the request was being made on behalf of FBI director (Robert) Mueller, and I said no,” Eytan testified Thursday. “… I made it absolutely clear.”

The judge in the case, Carlos Samour, is expected to release a written ruling at a later date.

John Ingold: 303-954-1068, jingold@denverpost.com or twitter.com/john_ingold