By Keith Coffman

CENTENNIAL, Colo. (Reuters) - Lawyers for Colorado movie massacre gunman James Holmes asked that jurors in his murder trial be questioned on Monday about whether they saw reports of the death sentence given to the Boston marathon bomber, arguing it could affect their impartiality.

Prosecutors have said they will seek the death penalty if the 27-year-old Holmes is convicted for killing 12 people and wounding 70 during the midnight premiere of a Batman film at a Denver-area multiplex in July 2012.

The prosecution objected to asking the jurors about the Boston verdict, but was overruled. The jurors said nothing they had seen would stop them from rendering a fair verdict, and the judge allowed all members to remain on the jury.

Some observers have drawn parallels between the Colorado trial and that of Dzhokhar Tsarnaev, 21, who was handed a death sentence by a federal jury on Friday for his role in the 2013 Boston attack that killed three people and wounded 264.

Holmes, a former neuroscience graduate student, has pleaded not guilty by reason of insanity to multiple counts of murder, attempted murder and explosives charges.

The 19 women and five men of the jury in his case have been told repeatedly by Arapahoe County District Court Judge Carlos Samour not to discuss the case, and to avoid any news reports of the high-profile proceedings.

On Monday, Holmes' public defenders called for jurors to be asked whether they had seen coverage of the Tsarnaev verdict over the weekend. One lawyer held up a front page story in the Denver Post newspaper as an example.

"We're concerned because of the obvious parallels," said defense attorney Kristen Nelson.

The prosecution objected, saying the issue should have been raised earlier. Samour noted to the defense that, by asking the jury about the Boston case, he would in fact be bringing it to their attention.

Samour overruled the state's objection, and when the jury was brought back in they all told him nothing they saw would stop them from being impartial.

Holmes' lawyers say he suffers from schizophrenia and was not in control of his actions when he plotted and carried out the attack.

The prosecution says he did it because he had lost his girlfriend and career, and had a "longstanding hatred of mankind."

The prosecution has been interspersing crime scene technicians and other factual witnesses with graphic testimony from survivors.

On Monday, the jurors heard from restaurant worker Louis Duran, who went to the movie with a friend. They were both injured, and Duran said he still has shrapnel in his chest, arm and knee today.

"I didn't think I was going to make it," he said.

(Reporting by Keith Coffman; Writing by Daniel Wallis; Editing by David Gregorio)