(CNN) -- A man suspected of fatally shooting a Utah sheriff's deputy was arrested Monday after a manhunt that lasted days, police said.
Scott Curley is suspected in the shooting death last week of Kane County, Utah, Deputy Brian Harris.
The incident began Wednesday night, when Curley "apparently assaulted a janitor at the local high school," said Alan Alldredge, emergency services director at the Kane County Sheriff's Department in Kanab, Utah.
Efforts to find Curley after that incident were unsuccessful, but officers from Kanab spotted him on Thursday and began pursuing him on foot. They called in their counterparts from nearby Fredonia, Arizona, for help as he headed into that state, he said.
"Apparently, with his knowledge of the area, it's possible he knew of a spot where he could ambush the officers," Alldredge said. "He was laying in wait underneath a tree. When these officers came up over the rise, he had his sights on them and fired upon them."
Harris, a 13-year veteran of the department, died after being hit by a shot from a high-powered rifle. Curley was able to escape.
Police had combed the rugged terrain south of the Utah-Arizona border for days in search of the suspect
He was arrested early Monday, after authorities received a call about 12:21 a.m. regarding a suspicious person carrying a rifle in a subdivision near the state line, the Coconino County, Arizona, Sheriff's Office said. Responding officers found Curley, who surrendered about 12:50 a.m.
Curley "appeared very tired" when taken into custody, said Jim Driscoll, chief deputy for the Coconino County sheriff. He said authorities spied Curley using night-vision equipment, giving him an advantage.
Police believe he might have been trying to enter a home for supplies. "I would think that's what drew him to a home ... maybe food or drink," said Kane County Sheriff Lamont Smith.
Curley "was in possession of the rifle suspected to have been used in the murder of Deputy Brian Harris," the Coconino County Sheriff's Office said in a written statement.
In all, 121 law enforcement personnel from 21 agencies were involved in the manhunt, Driscoll said.
Because the shooting of the deputy occurred in Arizona, the Coconino County Sheriff's Office will pursue extradition and prosecution on a warrant for first-degree murder, the sheriff's office said.
Curley was being interviewed by detectives on Monday. Smith said he was taken to a detention facility in nearby Washington County, Utah. The case is "potentially a death penalty case," Driscoll said.
Authorities are investigating whether anyone had assisted Curley, Driscoll said.
Smith said he told Harris' widow of the arrest, and "she was elated, she was overwhelmed, thankful." Authorities who had been searching for Curley received grateful e-mails from her Monday, he said.