Someone or something is killing America’s precious and majestic national symbol — the bald eagle — in rural Maryland, and animal protection groups are hot on the case.

According to the Center for Biological Diversity, 13 dead birds have been discovered in the region, causing a number of wildlife organizations to pony up thousands as a reward to whoever can lead authorities to an arrest and conviction.

So far, there’s about $25,000 on the line in total from three groups, including the United States Fish and Wildlife Service which has pledged $15,000.

This from CNN:

Four of the dead eagles were found by a man who was searching a field for shed deer antlers Saturday near Federalsburg, in Maryland’s Eastern Shore near the Delaware border, according to Maryland Natural Resources Police spokeswoman Candy Thomson.

He called the state agency, and wildlife officers found nine more carcasses after searching the area, Thomson told CNN.

It is “the largest die-off in one area in Maryland in 30 years,” Thomson said, citing an incident in which eight bald eagles were found dead of suspected poisoning, though testing did not provide conclusive answers.

The cause of death in this die-off is still unknown.

The remains of the deceased eagles are currently being studied at a one-of-a-kind federal forensics lab in Oregon. A report will be released in the coming weeks based on the facility’s findings.

Bald eagles are protected by the Bald and Golden Eagle Protection Act (enacted in 1940) and the Migratory Bird Treaty Act (enacted by 1918).