The last known U.S. slave ship is too “broken” and decayed to be extracted from the murky waters of the Alabama Gulf Coast without being dismembered, a task force of archaeologists, engineers and historians announced following a yearslong investigation.

The task force headed by the Alabama Historical Commission said Thursday that the Clotilda, the last ship known to transport enslaved Africans to the United States, had been broken in half by a large vessel and severely eroded by bacteria. The 500-page report says that the “responsible” way to memorialize the ship is to protect it under the water where it was discovered in 2019.

“There is no other site in the world that presents such physical evidence as the Clotilda,” said James Delgado, a lead marine archeologist on the investigation who said the priority was preserving that physical evidence. “The Clotilda is the scene of the crime, so everything we did was in that crime scene investigation manner.”

The wooden schooner at the heart of the investigation was commissioned in 1860 by Timothy Meaher, one year before the Confederacy was created and decades after the importation of slaves was made punishable by death in 1808. Captained by William Foster, the ship traveled to West Africa and illegally smuggled 110 Africans back to Alabama. Foster then attempted to burn and sink the ship to hide the crime.