MOAB, Utah >> Authorities hunting a gunman who critically wounded a Utah park ranger named a person of interest in the case as they came up empty Sunday in a second day of searching for a suspect in a rugged Utah canyon.

Grand County Sheriff Jim Nyland said late Sunday night that he was seeking to question 40-year-old Lance Leeroy Arellano.

He said in a release that the Sanpete County resident has been identified as “possibly being involved in the shooting” of 34-year-old Brody Young outside of Moab Friday night. Young remains in critical condition.

Throughout the day Sunday, more than 160 officers from around the state searched an area near the Colorado River southwest of Moab, an area famous for red rock canyons and natural arch formations.

The search near Dead Horse State Park began after Young was shot three times Friday night while patrolling the popular Poison Spider Mesa Trail.

The search area consisted of 15 square miles of rugged terrain that authorities say has likely given the gunman the “upper hand” in avoiding capture, Nyland said. Three helicopters were included in the search Sunday and authorities were also searching freight cars along an area railroad line.

“He pretty much knows where we are at all times because of the number of people we have,” Nyland said at a press conference.

Sunday night, authorities scaled back operations for the second night in a row, leaving about 20 officers in the search area until morning, which the hunt would resume in full force, according to a report by KSL-TV.

On Saturday, authorities tracked the man’s footprints in a canyon along the Colorado River, recovering his rifle, backpack and a tattered, bloody T-shirt. However, Nyland said authorities still believe the man is armed, the Salt Lake Tribune reported.

The backpack contained canned goods and an empty gun holster believed to hold a .40-caliber handgun, according to the newspaper.

“We consider this individual armed and dangerous. As we’re tracking him we have to keep that in mind — the security of the trackers — and we’re having to move pretty slow,” Nyland said.

Authorities found a new set of footprints they were tracking on Sunday before sunset.

Young stopped a vehicle at the trailhead, and gunfire was exchanged between him and the driver, said parks spokeswoman Deena Loyola. It was not clear what sparked the violence, and Nyland said authorities have not yet been able to interview Young.

Nyland had told The Associated Press that the ranger had been shot in the arm, leg and the stomach area, and he underwent surgery at St. Mary’s Hospital in Grand Junction. The hospital declined to comment.

The statement on the person of interest said Arellano is the owner of a 1999 silver Pontiac Grand Am that authorities suspect was used in the shooting.

It said Arellano has a criminal history that includes assault and drug charges and may be armed, dangerous and seeking medical help.

Department spokeswoman Crystal Alverez declined to say if authorities believe Arellano and the suspect being hunted are the same person.

Family members were stunned by the shooting, saying Young has faced tense work situations but never alone. His family says he is a friendly, outgoing ranger.

Young and his wife, Wendy, have three children. The couple are outdoor enthusiasts who once worked as river guides in the Moab area.

Loyola said Young, who has been a ranger for more than four years, was speaking to medics and at the hospital.

The Poison Spider Mesa trail to the south of Moab is among Utah’s best-known biking runs with enthusiasts calling it an especially challenging but scenic loop that rises more than 1,000 feet into the surrounding countryside.