DENVER (Reuters) - A Colorado judge ruled on Thursday that accused theater gunman James Holmes will tethered to the courtroom floor by a cable for security reasons during his murder trial, but denied a defense request to sequester the jury.

James Holmes sits in court for an advisement hearing at the Arapahoe County Justice Center in Centennial, Colorado June 4, 2013. REUTERS/Andy Cross/Pool

Holmes is charged with multiple counts of first-degree murder and attempted murder stemming from a shooting rampage last July that killed 12 moviegoers during a midnight screening of the Batman film "The Dark Knight Rises" at a suburban Denver cinema.

Fifty-eight other people in the audience were wounded by gunfire and a dozen others suffered other injuries in the ensuing pandemonium.

Prosecutors have said they intend to seek the death penalty against Holmes, 25, if he is convicted.

The California native and former University of Colorado graduate student of neuroscience has pleaded not guilty by reason of insanity.

Holmes' public defenders have argued that allowing jurors to see their client handcuffed and shackled, as he has been in all of his court appearances so far, would unfairly prejudice them against the accused gunman.

Arapahoe County District Judge Carlos Samour Jr. agreed, but said Holmes poses a security risk and that public safety requires that he be restrained during the proceedings.

Holmes will wear a harness under his street clothes with a cable bolting him to the courtroom floor, the judge said.

The cable will be visible to jurors, Samour said, but should be indistinguishable from computer cords emanating from the defense table.

In a separate ruling, the judge denied a defense motion requesting that jurors be sequestered during the trial, which is scheduled to start in February 2014 and is expected to last for about four months.

Jury sequestration is "an extremely rare procedure," the judge said, noting that it would be expensive and impractical to keep jurors sealed off from the outside world for the duration of the trial.

Defense lawyers can renew the request later if issues arise that warrant another look, Samour said.