CENTENNIAL, Colo.--Flags outside the Arapahoe County Detention Facility flew at half-staff Saturday for the victims killed and wounded in the Aurora movie theater massacre.
Beyond the jail's walls sits the man police say is responsible for the rampage, one of the worst mass shootings in United States history.
"The inmates know he's in there, but nobody's saying anything," said a woman leaving from visiting a jailed relative. "I wonder if he's on suicide watch. He should be."
"We typically do this in high-profile cases," Arapahoe County Sheriff Grayson Robinson told Reuters. "It has nothing to do with any specific threat."
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The jail is located 15 miles southeast of downtown Denver, next door to the Broncos' headquarters.
Holmes' court-appointed attorneys don't want the suspect talking either. A request to interview him was denied.
"Per the inmate and his legal counsel, there will be no interviews at this time," Undersheriff David Walcher said in an email to Yahoo News.
For a second day, police declined to say if Holmes was cooperating with investigators. Aurora Police Chief Daniel Oates said FBI behavioral scientists are assisting investigators in profiling the suspect.
"Over the coming weeks and months, they'll be working very closely with us to try and figure out what his motivation was," Oates said.
According to jail records, Holmes is being held without bond on multiple charges of first-degree murder. How many charges and whether prosecutors will seek the death penalty have not been determined.
Seventy people were shot or injured by the gunman. The 12 killed ranged in age from six to 51 years of age. Two others remain in critical condition.
It was about 15 minutes into "Dark Knight Rises," the latest film in the Batman franchise, when Holmes, suited in full combat gear, allegedly entered through an exit door carrying three guns, including a military-style rifle capable of shooting 50 to 60 rounds per minute. He didn't resist when officers arrested him behind the cinema minutes after the shooting stopped.
However, police did find his nearby apartment to be booby-trapped with explosives. Investigators said they believe Holmes purchased 6,000 rounds of gun ammunition and bomb-making materials over the past four months. Late Saturday, CBS News reported the suspect had spent an estimated $15,000 on his arsenal of guns, chemicals, explosives and ammunition.
"What we're seeing here is evidence of, I think, some calculation and deliberation," Oates said Saturday.
Police believe all the gun purchases were legal, but said they are also tracking the shipments of the bomb-making materials he received in the mail. Oates didn't rule out that others could be charged.
"I guess anything is possible," he said. "It's a long investigative process and we'll just have to see where it ends up."
The judicial process starts Monday morning when Holmes is due to make his first appearance in district court.