People in jail aren't supposed to have cell phones.

But across America, one way or another, they're getting them.

In Maryland, inmate Patrick Albert Byers Jr. used one to arrange the murder of a witness in a homicide case, prosecutors say. He's facing the federal death penalty.

In Canada, imprisoned drug lord Rivo D'Onofrio used cell phones to make thousands of calls to his cronies. "He gabbed for hours and hours," a prosecutor said.

In a notorious local case, drug kingpin Ronald Whethers used cell phones to run his narcotics empire from the Westmoreland County Prison, leading to a state law prohibiting cell phones behind bars.

Corrections officers at home and abroad are struggling with how to keep inmates from wreaking havoc by phone.

"They're pulling their hair out," said Louis Garzarelli, a former U.S. Bureau of Prisons intelligence officer who teaches criminology at Mount Aloysius College in Cambria County.

"They really don't know what to do about it. The damage that is done is unaccountable. They don't know how many are in there."

The problem has reached absurd proportions in some states.

A Maryland legislator was stunned when a prisoner called him on a cell phone to complain about his prison.

In Texas, a warden received a call from the mother of an inmate asking why her son was getting such poor cell phone reception behind bars.

Some other countries have it a lot worse.

Two years ago in Brazil, hundreds of incarcerated gang members used cell phones to coordinate riots at 73 prisons and attacks on the outside against police. The wave of violence paralyzed the state of Sao Paulo and left 160 people dead.

The United States has seen nothing on that scale, but officials are seizing thousands of cell phones nationwide.

Some are brought in by visitors, who have been known to hide them in body cavities.

But the majority are supplied by guards, often in exchange for bribes. The going price: $500. In Pennsylvania, corrections officers can themselves end up in jail under the law inspired by the Ronald Whethers case in 2000.

In Cambria County, for example, former part-time officer Donald Burkett is awaiting trial on a charge of letting an inmate use his personal cell phone to call his girlfriend. A second guard is under investigation.

"It's not a problem in every jail, but it is in most jails," said John Prebish Jr., the warden. "You have everything from guards smuggling them in to inmates and visitors smuggling them in."

The state system generally gets high marks for cell phone detection, but it's not immune. At SCI Graterford, four guards were indicted last year on federal charges of supplying cell phones and drugs to inmates in exchange for bribes.

The newest threat behind bars is the SIM card, a tiny, portable memory chip that allows lots of prisoners to use a single phone.

The prison system simply hasn't kept up with communications technology.

"Cell phones become a huge threat to three people: the officers inside the prison, the prisoners themselves, and the public," said Terry Bittner, director of security products for EVI Technology, a Maryland company whose cell phone detection system is used in one Pennsylvania prison, some facilities in the federal system and elsewhere.

There are three ways to crack down: stop the phones from coming in, stop inmates from using them or stop the signals from reaching the prison.

But there are complications with all three.

No screening process, called "portal security" in prison-speak, works all the time.

In Pennsylvania, the Department of Corrections said it seized a total of eight phones, batteries or chargers from prison cells so far in 2008. Six of the system's 27 prisons didn't provide information on phone seizures to the department's public relations staff.

The department seized 15 last year and 10 in 2006.

But some other states seize hundreds in a given year. In California, for example, officials have confiscated 1,331 phones from prisoners so far this fiscal year.

How can Pennsylvania be finding so few? The state says it's because the phones don't get into prison in the first place.

"We really are that good," said Susan McNaughton, corrections spokeswoman.

Unlike many other states where guard unions have successfully resisted security measures, officers in Pennsylvania have to pass through metal detectors and are subject to searches.

"I think the numbers show that we are not experiencing problems to the extent that some other state DOCs are," she said. "I think that is attributed to the fact that we have a multi-pronged approach to keeping contraband, drugs and cell phones out of our prisons."

But others aren't so sure.

"Any state the size of Pennsylvania that is only finding eight phones probably isn't trying very hard," said Mr. Bittner, who admittedly is trying to market his company's detection system.

John Shaffer, the former No. 2 official in the state prison system and now a consultant whose clients include Mr. Bittner's company, agreed that Pennsylvania's screening process is excellent.

But he also said the state is probably missing some phones.

"No one can claim they're finding them all," he said.

At some lockups, officers rely on sophisticated electronic wands, which cost up to $15,000 each.

They work, but critics point out that the user has to be very close to the signal and that the device generates a lot of false alarms, such as setting off alerts on gum wrappers.

Many jails, tight on resources, stick with the low-tech approach.

"We just search all the time," said Ramon Rustin, warden at the Allegheny County Jail. "We do sweeps. We will lock down the units and send in dogs. We're searching for everything, not just cell phones." He said his staff has found one phone in his four years in charge.

Dogs can be effective, at least according to companies that market them. But some security experts aren't convinced a dog's nose is the best technology for the 21st century.

"I can't believe we're down to dogs," said Mr. Garzarelli. "They should be able to come up with a device to track the signal."

Actually, they have.

Companies such as EVI Technology and AirPatrol make systems that use radio frequency sensors hooked up to a computer that displays a map of the prison. If someone is using a phone, a technician at the computer will see a flashing blip on the screen.

So why isn't everybody using it? Experts say the problem is cost, which is dependent on the size of the prison, the age of its infrastructure and the number of sensors requested to cover a given area.

EVI counters that its system isn't that expensive, considering that it's a one-time cost and it provides 24-hour coverage. The company said the price tag ranges from $25,000 for a small Virginia jail to $80,000 for a 3,000-inmate federal facility.

"It's cost prohibitive," said Warden Prebish. "The easiest thing is to jam the signals."

Cell phone jammers are illegal in the U.S., even in prisons, under the 1996 Communications Act.

But an upcoming experiment in South Carolina, and a series of petitions pending before the Federal Communications Commission, are forcing a hard look at whether they should be.

Next month, a Florida company called CellAntenna plans to demonstrate its jamming technology at a South Carolina prison, risking enforcement action by the FCC that could include fines of up $16,000 a day.

Jamming is legal in other countries, although a lack of accuracy has been a complication in urban areas. Jammers set up at a prison in Brazil, for example, also knocked out cell service to 200,000 people who lived nearby.

But CellAntenna says its system offers pinpoint accuracy.

At the same time, various commercial interests have petitioned the FCC in the last two years on both sides of the jamming debate.

CellAntenna has asked that jamming equipment be made available to state and local law enforcement. Another company, GEO Group, wants state and local prisons to be allowed to jam signals.

The cell phone industry, threatened by any attempt to jam its signals, has asked that jamming equipment remain illegal.

As it is, the FCC has authority to grant waivers only to federal agencies, not state facilities, and then only in cases in which the public is in imminent danger. Under those guidelines, even the federal prison system doesn't qualify for jammers.