Prosecutors will consult with the survivors of a mass shooting in Colorado and the families of those who were killed before deciding whether to seek the death penalty for the suspected shooter.

James Holmes, the 24-year-old suspected gunman in the Colorado movie theatre shooting, appeared in court for the first time Monday looking stunned, unshaven and with a shock of dyed orange-red hair.

His case was put over for a week.

Speaking to reporters outside the court after Holmes' appearance, District Attorney Carol Chambers was asked whether prosecutors would be seeking the death penalty.

She said the decision would ultimately rest with the prosecutor, but said victims and their families would be consulted as part of that process.

"If the death penalty is sought, that is a very long process that will impact their lives for years...so if that happens we would want to get their input," Chambers said.

Chambers also said there is the potential for "many" charges to be laid against the accused, but that decision has not been made at this point.

She said prosecutors would be speaking with all the victims in the coming weeks and suggested it could take a year for the case to go to trial.

Holmes is accused of killing 12 people and wounding 58 in the shooting spree at a premiere of "The Dark Knight Rises" in Aurora, Colorado last week.

It is expected that formal charges will be filed on July 30 during his next court appearance.

Holmes appeared subdued Monday, sitting beside his lawyer in a burgundy prison jumpsuit and at times slowly closing his eyes -- prompting some to ask whether he was on medication.

Holmes’ orange hair confirmed earlier reports that he had dyed it. New York City Police Commissioner Ray Kelly told reporters Friday that Holmes had coloured his hair and called himself the Joker -- one of the primary villains in the Batman comics and movies. Investigators would not confirm that information.

CTV News field producer Philip Ling was in the courtroom and saw the relatives of some of the victims in attendance. One man glared at the suspect the entire time. Once Holmes was led out of court, the man broke down in tears and hugged the woman sitting next to him.

The Associated Press identified the man as Tom Teves, whose son Alex was killed in the theatre.

Holmes has been held in solitary confinement at an Arapahoe County detention centre adjacent to the suburban courthouse.

There was word Monday that Holmes isn't co-operating with police and has refused to speak to anyone following the immediate aftermath of his arrest, including lawyers.

According to Aurora Police Chief Dan Oates, Holmes has been assigned a public defender and has "lawyered up" since his arrest on Friday.

"He's not talking to us," Oates said.

A lawyer representing Holmes’ family said their “hearts go out to the victims and their families.”

“The Holmes family would like to retain their privacy,” Lisa Damiani told reporters, refusing to answer further questions about Holmes or his relationship with his parents, who live in California.

Holmes was a doctoral student at the University of Colorado Anschutz Medical Campus until he dropped out in June. It isn't clear why he quit the graduate program or whether he demonstrated suspicious behaviour leading up to the attack.

The university said Monday it received two suspicious packages, but it was not immediately clear whether they are linked to the suspected shooter.

The packages were found on opposite ends of the campus and at least one building was evacuated for a couple of hours until the all-clear was given, a university spokesperson said. Police are investigating.

Holmes recently took an intense three-part exam to mark the end of the first year of his program. The exam is seen as an important milestone marker, where students assess their progress and either shift to full time research, or change direction.

The university will not say how Holmes did on the exam, citing privacy concerns.

Meanwhile on Sunday, residents of the Aurora area held a prayer vigil and U.S. President Barack Obama arrived to meet with the families of the victims.

Obama said he told the families that "all of America and much of the world is thinking about them."

Obama met with the families at the University of Colorado Hospital in Aurora, the facility where many of the shooting victims were treated. In total, 10 victims remain at the hospital, seven with critical injuries.

At the vigil on Sunday night, several thousand people gathered to grieve and heal. A banner at the vigil read: "Angels Walk With Those Who Grieve."

With files from The Associated Press