It took more than 18 months, but the investigation of the plundering of the Kanupa burial cave in South Kohala finally has yielded a federal charge, a welcome signal that the criminal justice system is taking the prosecution of such thefts seriously.

It's also a signal that these burial caves are continually at risk of looting, and authorities need to confront the persistent issue of security.

Last week, Big Island resident John Carta was charged with transporting for sale and profit cultural items obtained in violation of a federal burial-protection law. If convicted, Carta could serve up to a year in prison for the misdemeanor offense.

Given the lucrative attraction of artifacts trafficking, the penalty alone may not be sufficient to discourage further thieving. It's been suggested that the objects can fetch $5,000 to $20,000.

Clearly, the lava-tube enclosures that ancient Hawaiians held to be sacrosanct are more vulnerable in these crime-ridden times.

It's encouraging that federal agents plan to continue the investigation. When artifacts claimed under the federal law protecting Hawaiian burials are released for reburial, there needs to be a plan for security that addresses the multiple openings to many of these caves.

Federal and state officials also need to consider their responsibility to provide additional security with regular site inspections. The objects in dispute in the Forbes Cave litigation come to mind. With the prominence of that case, these cultural treasures remain at risk.

State historic preservation officials, and their enforcement team, could have done more to patrol the Kanupa site, which sits on state land. Both cases underscore that the job doesn't end when burial artifacts are returned to the earth.

They can't be assumed to be resting in peace.