BRECKENRIDGE, Colo. (AP) _ Searchers who found the bodies of three skiers buried by a massive avalanche returned today to a Rocky Mountain peak, using metal detectors and an infrared device in the hunt for a fourth victim.

Two bodies were found Thursday in the hard-packed snow on the 11,600-foot Peak 7 near the Breckenridge Ski Area, about 65 miles west of Denver.

One body had been found hours after Wednesday's avalanche, which left a swath of snow a half mile across and 40 feet deep.

Some 100 searchers returned to the mountain today, said Summit County Sheriff's spokesman Ron Milhorn. Several of the search dogs wore red-quilted blankets to combat temperatures in the low teens.

While the search went on in the out-of-bounds area, skiers packed the ski resort slopes yards away as snow fell.

More than 200 search and rescue team members and volunteers used dogs and long aluminum probes Thursday, digging each time a pole struck something hard in the snow. One volunteer said it was like shoveling wet concrete.

Dynamite was detonated at the top of the peak to break loose any other snow masses, and searchers wore tiny radio transmitters in case they were trapped in a snowslide.

Summit County Sheriff Delbert Ewoldt said the infrared device, loaned by Colorado School of Mines, should be able to detect any object suspended in the deep snows left by the avalanche.

Milhorn said the workers were tired and cold by the time the search was halted Thursday evening.

''They haven't had much of a break,'' he said.

The temperature reached only about 20 degrees Thursday, and lows of zero to minus 5 degrees were forecast for this morning.

''We knew that we were going to find people that weren't alive,'' said volunteer Jaya Zar of Glenwood Springs. ''But finding those people and knowing their families will be in peace, that is worth it.''

The dead were identified as Martin Donnellan, 21, of Peekskill, N.Y., whose body was found Wednesday; and New Zealanders Paul Way, 23, of Auckland, and Nick Casey, 23, of Cambridge. The three had been skiing together, authorities said.

Ewoldt said the fourth man had been skiing in another area of mountain in the Arapaho National Forest with his stepbrother, who managed to escape. Neither man was identified by the sheriff.

All the men had been skiing about three-quarters of a mile north of the Breckenridge Ski Area on a section of the mountain marked with signs describing it as dangerous and out of bounds to skiers, said Breckenridge spokesman Jim Felton.

Mike Tyack, a 31-year-old South African who outran the slide, said some skiers disregard the warnings because of the challenge. ''It's deep powder, and the guys get pretty bored just skiing the runs. We're all aware of the risks.''

Tyack, who aided in the search, said he had planned to join the ski party but was unexpectedly called to work as a bartender at an area resort.

''I was meant to be with them at the top of the peak,'' he said. ''I'm thankful, but I'm also sad for the others.''

The three men whose bodies have been recovered had been skiing with roommate Tim Kirkland, an Australian, when the slide occurred.

Kirkland, who outran the snowslide, said the group saw the out-of-bounds signs and ''skied under the ropes without stopping'' because the steep area ''looked attractive.''

He said Casey lost a ski in the powder and the rest of the group waited for him to reattach the binding.

''We were sitting in the snow when one guy right away yelled, 'Avalanche 3/8' It looked like a huge cloud coming down,'' he said.

Witnesses said two skiers were at the top of the slope when the avalanche began, and Ewoldt said investigators had questioned them.

''I am not at liberty to discuss whether or not any criminal charges will be filed,'' he said.

The snowslide, described by authorities as the worst in Colorado's recent history, brought the state's avalanche death toll this year to seven. Four people have died in snowslides near Telluride in southwestern Colorado since Jan. 1.