Three Alabama residents arrested for digging for artifacts in the Vicksburg National Military Park likely will face federal charges, Acting Chief of Operations Patty Montague said Thursday.

The offenders, whom Montague refused to name until they are formally charged, were caught by a park ranger around 2 p.m. Sept. 3, with unspecified relics, a metal detector and digging tools.

It is illegal to dig in or otherwise disturb national parks or wildlife refuges, and those convicted of doing so can face hefty penalties and even jail time.

“Their focus was to come into the park and dig, they admitted that,” Montague said.

The Alabamans’ tools and the relics they found have been confiscated. The Southeast Archeological Center, which operates under the National Park Service and is based in Tallahassee, is assessing the damage and will produce a full report.

“What we’ve found, so far, is about 30 holes throughout the park, and they vary in size,” Montague said. “They also were digging on private property in the county just outside the park, but the property owner has declined to prosecute.”

Meanwhile, park officials are working with the U.S. Attorney’s Office in Jackson to determine under which U.S. codes the offenders, who have been released, may be charged.

“They’ve been advised that they’ll have a court date set, and if they refuse to show up, a warrant will be issued and a federal marshal will be sent to pick them up,” Montague said.

The last time rangers discovered holes in the park from relic hunters was 2007, said Montague. About $35,000 worth of damage was assessed, she said, and the case remains open because no one has been charged or identified as the culprit. Similar cases, with no charges or arrests, occurred in 1999 and 2000, she said.

“This is a chronic problem in the park,” Montague said of illegal relic hunters. “Most of the offenses happen at odd hours when a ranger isn’t available, so we’re very excited that we actually caught somebody in broad daylight.”

The VNMP — featuring nearly 1,400 monuments, markers and tablets over 1,800 acres — is the city’s No. 1 attraction, drawing in an average of 700,000 tourists from around the world in recent years.