SALT LAKE CITY — Kevin Bushling marked his oldest son's 27th birthday last week at home, curtains closed, reflecting on happier times. Now he's bracing for a Father's Day believing both his boys are dead — the youngest by suicide last year and the other, an Army soldier, missing for more than a month in the remote Utah desert.

Authorities plan to search again Sunday for Army Spc. Joseph Bushling, who disappeared May 8 from the U.S. Army's Dugway Proving Ground after telephoning a fellow soldier to tell him he was out of gas, cold and walking without shoes, according to a sheriff's document.

The Dugway site was established in 1942 to study chemical and biological warfare and covers nearly 800,000 acres in the desert along the Nevada border. About 850 people live on the isolated base, which made news in January when the facility was locked down for nearly 14 hours after a vial of nerve agent disappeared. Officials later said the chemical was never unsecured but had been mislabeled.

Bushling's father fears the worst — that his son died of exposure or possibly that he stumbled upon unexploded munitions or even mustard gas. He fears the Army may be hiding something. Dugway officials deny any such assertion.

"I am glad they are still searching," Kevin Bushling said from his home in Russellville, Ark. He said he was shocked to learn several weeks ago that the search had been called off, but pleased with the resumption.

"At this point, I've come to the conclusion if they don't find him, I'll have to deal with the fact he's out there and I have to give up. I can't live my life every day waiting for the phone to ring," Bushling said.

The Tooele County Sheriff's Office and Dugway officials will conduct a ground and aerial search with help from a Utah Highway Patrol helicopter on Sunday.

Sheriff's Lt. Herman Herrera said authorities have received no new clues since recovering the soldier's borrowed vehicle and his Arkansas Razorbacks baseball cap last month off Army property. But he said there's a chance searchers missed something in the rugged mountainous terrain.

Herrera said authorities concentrated their search in an area between a locked gate on the northwest corner of Dugway and a site about six miles from where the vehicle was found. He said the hat was discovered between the two, leading searchers to believe the Army medic may have tried walking back toward the gate. Herrera also said that was the only area that seemed to have cell phone coverage.

A vehicle matching the description of one Bushling had borrowed was seen leaving Dugway's main gate at 3:45 a.m. on May 8 — 70 miles from where searchers eventually found the car. Herrera said Bushling and other soldiers would often drive out to the mountains just to get away.

Kevin Bushling said his eldest son had a tough year following a recent divorce and last year's suicide of his younger brother but he also was looking forward to a new post in Texas and a career as a nurse. He had been working as an emergency medical technician at Dugway and was scheduled to go to Colorado's Fort Carson on the very day he vanished. After that, father and son had planned a trip together to California then back to Arkansas before the soldier had to report to Fort Sam Houston in San Antonio.

Kevin Bushling flew to Utah three weeks ago to help with the search. He doesn't believe authorities have done enough.

He said he and his brother were helping searchers when they found a cave hidden by brush and a burlap sack. Inside were thousands of blasting caps and 55 pounds of dynamite.

Herrera acknowledged searchers found unexploded munitions on one search but had no information on their origins.

Dugway spokeswoman Paula Thomas hadn't heard of the munitions found off Army property but acknowledged Dugway personnel have worked to locate and clean up such sites on the base.

"Years ago when they tested with chemicals, sometimes people would just bury munitions," Thomas said. She said 216 such areas have been cleaned up.

Kevin Bushling said he was frustrated when sheriff's officials suspended the search indefinitely last month, and were reluctant to call in special personnel to search flooded areas of nearby Fish Springs National Wildlife Refuge.

Herrera said Fish Springs was 14 miles in the other direction from where the car was found and a helicopter search the first day turned up nothing.

"Nobody is hiding anything," Herrera said. "For the family to say somebody is covering up something is hurtful. I've been out there every search and we've had 30 and 40 volunteers working their butts off trying to locate this person."

Herrera said he is "hoping for a miracle" but is searching for anything, including remains.

Thomas said Dugway military police investigators are conducting a joint investigation with the Army's Criminal Investigation Division and several federal and state agencies.

"Between the county and the Army, we are investigating everything we can to find this soldier," Thomas said.

Meanwhile, Kevin Bushling just wants answers. The Army sent him paperwork last month classifying his son as AWOL, he said, but he doesn't believe his son disappeared willingly. And his son's supervisor said he had to be classified in some status, but also didn't believe the solder had gone AWOL.

"I'm looking at awards given my son for service in Korea, and at Dugway ... and then when I ask for help to find him, I don't feel I'm getting the same response," Bushling said. "They know he's out there."