Accused double murderer Tyler Miller is facing tighter restrictions in the Flathead County Detention Center after attacking a fellow inmate he believed was a friend of one of his alleged victims, Sheriff Chuck Curry confirmed Thursday.

Miller, 34, was arrested on Christmas Day hours after allegedly gunning down his ex-girlfriend, 35-year-old Jaimi Hurlbert, and her 15-year-old daughter Alyssa Burkett in his mother’s driveway west of Kalispell.

Miller, who had his last name legally changed from Cheetham in 2009, pleaded innocent Jan. 13 to two counts of deliberate homicide during an arraignment in District Court.

According to Curry, two days later — on Jan. 15 at about 8 p.m. — Miller was being led by a corrections officer to a courtyard where inmates are provided daily outdoor recreation.

As Miller waited near an elevator with a corrections officer, Curry said Miller turned his attention to a 39-year-old inmate who was being returned to his cell after visiting a friend.

“As they approached, Miller smiled at the other man” and exchanged words with him, said Curry, citing a report.

He said Miller then ran away from the corrections officer and “started swinging” at the other inmate. The two tumbled to the ground before officers were able to separate them.

“We don’t really think he hit him,” said Curry, who added that the man declined to press charges.

Miller apologized to corrections officers but said “he would take care of anyone who was a friend of Jaimi’s,” Curry said.

Miller already was being held in a maximum security unit within the jail but has since been placed under even tighter restrictions.

“His movements will be more closely monitored,” Curry said. “We’ll certainly change the way he moves in the facility.”

Miller angered Hurlbert’s family and friends after he appeared to smile and wink during his Jan. 13 arraignment.

He stared intently at her father, Butch Hurlbert, as he was being led into a courtroom for his initial appearance Dec. 27 and mouthed several words that Butch Hurlbert interpreted as a threat.

Prosecutors in the Flathead County Attorney’s Office still are considering whether to pursue the death penalty for Miller. Each of the deliberate homicide charges carry a maximum penalty of 100 years in prison or death.

Miller was arrested just before 5 p.m. Dec. 25, 2010, after allegedly shooting Hurlbert and Burkett with a .45 caliber handgun hours earlier in the driveway of his mother’s home on Block Crest Court west of Kalispell.

Family and friends said Hurlbert and Miller have a 17-month-old daughter and that Miller had become aggressive and erratic after Hurlbert ended their relationship.

Miller allegedly confessed to the murders during interviews with Flathead County Sheriff’s Office detectives, according to court documents.

A trial for Miller is tentatively scheduled to begin March 7.