Dwayne Keith Fitzen — "Shadow" to fellow inmates at the federal prison in Waseca, Minn. — was halfway through his 24-year sentence when prison officials decided to move him to a facility in California.

To make the transfer, the Bureau of Prisons did something fairly routine for the government agency: It bought Shadow a one-way bus ticket and sent him, traveling unsupervised and unmarked, on the two-day trip.

Fitzen was 55 at the time, a motorcycle gang member convicted of dealing cocaine. He got off the bus in Las Vegas, about 400 miles short of his scheduled destination, and became a fugitive. Five years later he's still at large.

Since April 2006, the Bureau of Prisons has allowed 89,794 federal inmates to be transferred without escorts, traveling mainly by bus.

The rationale behind the unescorted transfers, according to bureau spokeswoman Traci Billingsley, is purely economic: Having prison officials, or U.S. marshals, in charge of moving inmates who have been prescreened and deemed low-risk would be incredibly expensive, she said. Exactly how much it would cost, the Bureau of Prisons doesn't know.

Historically, fewer than 1 in 500 inmates being transferred without escorts have absconded, Billingsley said. Although the federal agency doesn't have the exact numbers for recent years, that calculates to no more than 180 inmates since 2006. The Bureau thinks this number is small enough to justify the cost-saving program, though bus companies don't agree.

Bus companies have no idea when inmates are being transferred. Greyhound in particular has asked the federal prison system several times to stop transferring convicts on its fleet.

"We feel this is an inherent safety risk to our customers and our employees as well," Greyhound spokeswoman Abby Wambaugh said.

Greyhound executives learned of the transfer program in 2005 and complained. Prison officials tried to appease them, writing a letter noting that of the 77 inmates who escaped during unescorted transfers from October 2003 to September 2005, all but 19 were recaptured or returned to custody.

Fitzen is one of those 19.

Inmates going Greyhound have been gravy for TV news reporters who stumble upon the subject every few years and attack it with a vengeance. Often, their reports mention Shadow's Las Vegas escape.

The truth is, unescorted transfers have been happening since the early 1990s, though Billingsley didn't immediately have the program's start date or the number of unassisted transfers for years before 2006.

Billingsley also did not have numbers for how many inmates have fled bus transfers in Nevada. But even one escaped inmate is enough to draw public ire, as well as ratings for TV news stations.

In its defense, the Bureau of Prisons offers a fact seldom addressed in reports on the subject: Of the almost 90,000 inmates who have been transferred alone since 2006, the vast majority — 94 percent — were being sent to halfway houses.

Inmates in halfway houses, where they are helped with finding jobs and integrating back into society, are allowed to ride the bus and walk around town freely. Make it to your final destination, in other words, and you can ride the bus all you want.

But not every inmate is being transferred to a halfway house. In the past three years 5,347 federal inmates have been transferred unescorted to minimum-security facilities, more commonly called prison camps.

Prison camp inmates are often sent into communities to do various jobs, repairing buildings, cleaning roads and so on. This work is sometimes performed without a staff escort, or under intermittent supervision, according to the 2005 letter from prison officials to Greyhound. The implied point: The bus isn't the only opportunity to escape.

Fitzen was headed from Minnesota to the Lompoc Federal Correctional Institution — a low-security facility about 175 miles outside of Los Angeles. If he ever gets caught, he'll be in a world of trouble. This is one of the "disincentives" prison officials say keep unescorted inmates from fleeing. Most inmates who run are ultimately caught and then face more charges, Billingsley said.

Fitzen got off the bus in Las Vegas, then went to a bank and withdrew $12,000 in cash, according to U.S. marshals, who are still looking for him. He has reportedly been spotted a few times since his escape, but has otherwise lived up to his nickname.