James Holmes, the 24-year-old man suspected of the Colorado theatre massacre which resulted in 12 deaths and more than 50 injuries, is refusing to cooperate with authorities as in the run-up to his first court appearance.

Since his arrest, Holmes has been held in solitary confinement for his own safety at a detention facility in Colorado's Arapahoe County, which covers the city of Aurora where the massacre took place.

According to Dan Oates, Aurora's chief of police, Holmes is "lawyered up" and "not talking to us".

Holmes will face multiple charges of murder, together with aggravated assault and weapons violations, when he appears in court.

Neighbours of the former medical student said his behaviour was ordinary. One described him as "just an average person".

"The people who would be suspicious would be people that are mentally ill and show some type of weirdness,2 said one.

Shooting range rejection

It is alleged that Holmes set off gas canisters and used a semi-automatic rifle, a shotgun and a pistol to open fire at theatre-goers who had gone to the midnight screening of The Dark Knight Rises, the last in Christopher Nolan's Batman trilogy.

According to reports, he started buying guns at a store near Denver two months before the shooting rampage, and received at least 50 packages in four months at his home and at school.

However, his application to the Lead Valley shooting range was rejected because of his "weird" tone of voice, said range owner Glenn Rotkovich.

Rotkovich said that when he rang Holmes to call him in for a mandatory orientation day, he went through to a voicemail message which was "bizarre, guttural, freakish at best", according to AP.

The university declined to release any details of Holmes's academic history to news agencies. A former high school classmate, Ritchie Duong, told the Los Angeles Times that Holmes liked to play cards and video games.

Duong added that Holmes' performances at university were excellent.

"I had one college class with him, and he didn't even have to take notes or anything. He would just show up to class, sit there, and around test time he would always get an A."

Investigators found a Batman mask inside Holmes' apartment after they finished clearing the home of booby traps and ammunition.