RAPID CITY, S.D. (AP) — Federal officials in South Dakota say 15 people have been indicted for illegally trafficking eagles and other migratory birds after a two-year undercover operation.

U.S. Attorney Randy Seiler said Monday that officials expect “significant” additional federal charges in the case.

Seiler says the investigation focused on trafficking of eagles and eagle parts such as feathers for profit. Authorities say the case likely involves hundreds of birds including more than 100 eagles.

Seiler described one operation as a “chop-shop for eagles.” Informants allegedly purchased bird parts such as eagle wings. Those accused include people from Iowa, Nebraska, South Dakota and Wyoming.