Police are "pretty confident they'll find him," said Coconino County, Ariz., Sheriff's Chief Deputy Jim Driscoll.
The sighting was outside a perimeter set up by law enforcement to contain Curley, so additional officers were sent to investigate the Kanab-area sighting.
"Rather than just pack up and move everyone away from our perimeter, we dispatched a number of units up there to determine if it was him," Driscoll said.
Police on Friday were vigilant in looking for Curley, at one point stopping a semi truck in Kanab and searching the cab.
Driver Neal Breinholt, of Salt Lake City, said he stopped his rig just east of Kanab on Thursday night to sleep in his sleeper cab with his blind pit bull, Stu.
"I didn't know they were looking for someone so I slept with my windows down," said Breinholt.
He said before he began driving Friday, a law enforcement official asked him if there was anyone in his cab, and Breinholt said there was not.
As he entered Kanab, he was stopped by police, who surrounded the rig and again asked if there was anyone in his cab.
"I said, 'No, unless I'm as blind as my dog,'" said Breinholt, who was given the all clear and drove out of town.
Speaking at a 1 a.m. Friday news conference in Fredonia, Driscoll said Curley's friends have told police that the suspect had stored food in the mountains in so-called "spider holes." Driscoll said Curley still has the high-powered rifle he used to shoot Harris but investigators don't know if he has any other weapons.
Driscoll said a "variety of tactics" are being considered to find Curley, and police tried to prevent Curley from sleeping during the night. He declined to elaborate.
A temporary first-degree felony murder warrant has been issued for Curley, the Coconino County Sheriff's Office said.
Driscoll said officials intend to send in eight or nine police dogs to find and subdue Curley, rather than put more people in the line of fire.
"They would take care of the suspect," he said.
Dozens of police officers from Arizona and Utah were at a staging area in Fredonia as of midnight. Driscoll said some sheriffs and police departments even sent officers without being asked. He said 121 officers from 21 agencies were on the scene.
Curley, 23, was being sought in connection with burglaries in Kanab and may also be a suspect in a burglary of a school in Fredonia, during which the bandit pointed a rifle at a custodian.
A search of Utah and Arizona court records shows a history of misdemeanor crimes for Curley, such as intoxication and fighting. But Kane County Sheriff's Sgt. Alan Alldredge said police in Fredonia and Kanab knew Curley well.
"He just seems to be one of those individuals we've been dealing with over and over," Alldredge said. "Just petty crime type things."
Driscoll said Harris and another officer pursued Curley into Arizona. A foot pursuit lasted three or four miles. The two were following tracks when Curley fired at and killed Harris, Driscoll said.
Driscoll confirmed Curley has fired at other officers but no one else has been injured.