They came to Manassas National Battlefield Park armed with metal detectors and shovels, ready to find articles left by the Civil War soldiers who lived and died on the land.

What they got was arrested. And worse yet, embarrassed. As part of a plea agreement, the two men have taken out half-page advertisements in the Potomac News that begin "Relic Hunters Beware."

After a rundown of the federal Archaeological Resources Protection Act of 1979 and associated penalties, the ad continues, "We can attest to the fact that federal enforcement of this and related statutes in the Eastern District of Virginia is strong." The ad is signed, "Caught and Criminalized."

The advertisements cost $5,000. It cost the pair another $1,094 for the park to refill some 40 holes the men dug, said Assistant U.S. Attorney Chuck Rosenberg. Also, the metal detectors were confiscated.

"Nowhere, in a national park, is anyone allowed to metal-detect for anything," said Manassas National Battlefield Chief Ranger Kim Coast. "What was even worse was, they had disturbed an area that was already slated to have archaeological work done."

The area is known as the Confederate winter camp, where 600 soldiers stayed in makeshift cabins during the Civil War.

Coast is passionate in explaining why taking a few bullets or other items from parkland can't be condoned.

The National Park Service tries to preserve parkland in its most natural state. "People are disturbing things that future generations will never have a chance to see or learn about," Coast said.

Manassas Battlefield and other national parks across the country have sometimes suffered from their success. More than 273 million people visit the 375 parks each year, and many visitors decide to take something home as a souvenir.

According to the National Park Service, such "resource violations" have increased 123 percent in the past five years. Examples include taking Native American pottery shards, shooting bear and deer, collecting fossils and picking plants and flowers. At Petrified Forest National Park in Arizona, for instance, rangers believe visitors make off with more than 12 tons of petrified wood a year.

Locally, the Civil War parks draw the most attention from souvenir hunters. Superintendents at both Prince William Forest Park, a national park, and Leesylvania State Park say they have had some problems, but nothing serious.

"We're only about 500 acres, which gives us a lot more ability to keep an eye on things," said Leesylvania State Park Manager Jim Klakowicz.

At Fredericksburg and Spotsylvania National Military Park, another Civil War-oriented site, Supervisory Park Ranger Mike Greenfield cautions that legal relic hunters shouldn't be lumped in with those who take items from federal property.

"We're not trying to condemn people and their hobby," Greenfield said. "Relic hunting is an activity that's legal if it's done on private property and with permission. We're after the ones who do it illegally."

To make sure they're able to catch people who are taking relics from parklands, rangers are being trained to recognize relic hunters. They are taught to treat evidence of relic hunting as if it were obtained at a crime scene. This week, several national and local experts in archaeology will instruct park rangers in how to spot and stop relic hunting.

"The park rangers are very cognizant of this. We're trained better," National Park Service spokesman Terry Adams said. "It's a big deal when national treasures are being compromised."