Nearly 100 officers tracking a gunman in a rugged Utah canyon Saturday were believed to be closing in on the suspect accused of shooting and critically wounding a park ranger, authorities said.

Grand County Sheriff James Nyland said officers were able to pick up the man's footprints and found his rifle and backpack along the Colorado River, about 22 miles southwest of Moab.

"It could still take a while, but we think we're getting closer (to finding the suspect)," Nyland told the Salt Lake Tribune.

Searchers later found a tattered, bloody T-shirt that the suspect may have used to stanch a heavily bleeding wound, the sheriff said.

"We're going to put the blood hounds on that and see what they turn up," he told the Tribune.

The search near Dead Horse State Park began after Utah State Parks Ranger Brody Young, 34, of Moab, was shot three times Friday night while patrolling the popular Poison Spider Mesa Trail, authorities said.

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

"The park ranger was able to call in on the radio and advised that he was shot," the sheriff's office said in a statement on its website.

Young was in critical but stable condition at a Grand Junction, Colo., hospital, Loyola said. Nyland 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.

Authorities are focusing on the canyon because the suspect's silver Pontiac Grand Am was found nearby, about eight miles southwest of the shooting site. They're not sure whether the suspect was alone. The car's registered owner was from the Salt Lake City area.

"It's where the Colorado River goes into the canyon, so there are steep cliffs on both sides and other than walking up the river, he doesn't have anywhere else to go," Nyland told the Deseret News on Saturday, adding that authorities have contained the entire area.

Family members describe Young as a friendly, outgoing ranger who has faced tense work situations but never alone. They said they were stunned by the shooting.

"He's just not abrupt," Micheline Young, his stepmother, told the Deseret News. "He would never irritate someone to this point ... He's a wonderful guy, so upbeat and social. He's friendly to everyone."

He 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.