BILLINGS — Montana prosecutors have asked a judge to keep the trial in the murder of a high school teacher in her hometown of Sidney, after defense attorneys sought to have the case moved because of fears of bias among potential jurors.

In comments posted with newspaper articles about the 2012 murder of math teacher Sherry Arnold, some readers called for “Old West Justice” in the case and for the suspects to “hang from the nearest tree.”

But in court documents released Thursday, prosecutors argued to Judge Richard Simonton that any biased jurors could be “rooted out without difficulty” during the jury selection process for defendant Michael Keith Spell, 24, of Colorado.

“Blog comments on the Sidney Herald website, as bad as they are, are not sufficient evidence that a fair trial cannot be had in Richland County,” Deputy Richland County Attorney T.R. Halvorson wrote. “Not addressed by the blog comments or survey responses is the ability of jurors, despite preconceived notions, to lay aside their pretrial impressions and opinions and render a verdict based on the evidence presented in court.”

Defense attorneys in June filed a motion seeking to have Spell’s Jan. 6 trial moved more than 400 miles to Bozeman. They argued in court documents filed in June that a jury from the Sidney area would be tainted by the intense news coverage given to the case.

Bozeman is the hometown of lead defense attorneys Al Avignon and Lisa Bannick.

Halvorson said that if the judge decides a change is needed, there’s no need to go as far as Bozeman. He said the case could be moved to Dawson or Custer counties, or outside jurors could be brought into Richland County.

Spell could face the death penalty if convicted. He has pleaded not guilty, and his attorneys are seeking to have the death penalty ruled out in the case on the grounds that Spell is mentally disabled.

Arnold’s killing came amid dramatic changes in the Sidney area brought by an oil boom in Montana and North Dakota. Thousands of workers have descended on small towns and led to an increase in crime.

Spell’s co-defendant, Lester Van Waters Jr., pleaded guilty earlier this month under a deal with prosecutors that calls for him to receive a 100-year prison sentence with 20 years suspended. As part of the deal, Waters agreed to help the state’s prosecution of Spell.

Waters and Spell are accused of abducting Arnold during her morning jog in Sidney. The men either strangled her or held her face in mud or water until she died, prosecutors said.

Her body was found about two months later buried in a shallow grave in a field near Williston, N.D., about 50 miles away.