They were dubbed a modern Bonnie and Clyde, but unlike their illustrious predecessors, John McCluskey and Casslyn Welch did not go down in a hail of bullets.

Instead America's most wanted fugitives have been captured in the tamest of circumstances after police raided a remote campsite in Arizona where they had apparently been holed up for several days.

Not one shot was fired as the couple, who are cousins as well as romantic partners, were handcuffed and led away on Thursday night. Witnesses said Welch, 44, reached for a weapon when officers approached, but then thought better of it when she realised she was massively outgunned and outnumbered.

McCluskey, 45, had been enjoying 40 winks in his sleeping bag when the raid took place, and was too groggy to resist arrest. However he told officers that he regretted not having killed a US Forest Service ranger who stumbled on their campsite in the Apache-Sitgreaves National Forest earlier that day, leading to their eventual discovery.

The couple's capture ends a nationwide manhunt which has lasted for more than three weeks, covered eight states and seen detectives implicate them in a string of violent robberies together with the grisly double murder of an elderly couple from Oklahoma who crossed paths with the fugitives at a campsite in New Mexico.

It began on the night of 30 July when Welch threw a pair of bolt-cutters over the fence of a medium-security prison in Arizona where McCluskey, her fiancée, was serving 15 years for attempted murder. He cut a small hole, held the wire back with a dog leash, and crawled out with two other inmates, Tracy Province and Daniel Renwick.

Disoriented in the dark, only Renwick was able to find the getaway car. He drove off alone. The other three swiftly hijacked another car. But with nothing to eat, drink, or smoke they decided to carry out a string of violent robberies.

The ensuing manhunt led to sightings of the fugitives across remote swathes of the Rockies. Renwick was apprehended on 1 August in Rifle, Colorado. Province turned up in Wyoming, on 9 August. Detectives are now trying to piece together the freewheeling journey taken by McCluskey and Welch, who may also have got as far north as Montana and as far east as Arkansas, to work out what other crimes they committed.

"The nightmare is over," said a police spokesman, "but there's a lot more for law enforcement still to do."