Las Vegas - The fugitive couple had zigzagged across much of the West, ducking authorities, kidnapping two truckers and allegedly killing an elderly couple near a remote New Mexico ranch.

Though authorities were besieged with hundreds of tips about the elusive pair's location, the last credible sighting of John McCluskey and Casslyn Welch was Aug. 6. And that was in Montana.

Then, on Thursday, a ranger in the Apache and Sitgreaves National Forests in eastern Arizona noticed a campsite that looked somewhat odd.

The Gabaldon Campground is a favorite of equestrians, but instead of horses, the U.S. Forest Service ranger found an untended fire and a grayish Nissan Sentra nearly hidden amid spruce trees. The unkempt camper was so jittery, authorities said, that the ranger hurried from the campsite to check the sedan's license plate number.

The ranger had an inkling of what he'd find.

On July 30, McCluskey escaped from a medium-security private prison in Kingman, Ariz., where he'd been incarcerated for attempted second-degree murder. Welch, his fiancee and cousin, had allegedly tossed wire cutters over the prison barrier, allowing McCluskey and two convicted murderers to slice through a fence and flee.

Inmate Daniel Renwick took Welch's vehicle, unaware it held several weapons and $2,000. Before he was apprehended in Colorado on Aug. 1, he'd been selling cigarettes for gas money. Inmate Tracy Province accompanied McCluskey and Welch to New Mexico, where on Aug. 4 investigators found the charred bodies of a couple who had been on their annual camping trip.

Sometime before his Aug. 9 arrest in Wyoming, Province called family members, seeking help. Turn yourself in, they said, according to Fidencio Rivera, chief deputy U.S. marshal for Arizona.

But McCluskey and Welch - who authorities said romanticized themselves as a present-day Bonnie and Clyde - continued to dodge law enforcement, possibly showering at truck stops and slumbering at campsites.

Investigators hounded family and friends in Pennsylvania, Arkansas and San Diego, said David Gonzales, U.S. marshal for Arizona, in hopes of eliminating hiding places. Still, two weeks had passed since the couple was spotted. Then came the call from the ranger.

Acting on his tip, authorities discovered the battered sedan's license plate had been stolen in New Mexico, near where the elderly couple's bodies were found. The ranger, authorities surmised, had stumbled upon McCluskey and Welch.

At least a dozen officers swarmed the campground Thursday, and waited. Just after 7 p.m., with McCluskey sprawled on a sleeping bag outside a tent, they pounced.

McCluskey - shirtless, jeans-clad and with the word "Arizona" tattooed beneath his pectorals - was quickly taken into custody. Welch reached for a gun near the small of her back, but officers subdued her.

They told each other to be careful with Welch's weapon in case it had been used in the New Mexico slayings, Apache County Sheriff's Cmdr. Webb Hogle told reporters Friday. McCluskey, he said, interjected: "No, the murder weapon is over in the tent."

Had officers not sprung so quickly, Hogle added, McCluskey said he would have lunged for the weapon, in hopes of ending the three-week chase with gunfire.