A body located in Arizona waters at the Grand Canyon last week appears to belong to a person who disappeared as he traveled down the Colorado River with his dog on John Caldwella wooden raft, the National Park Service is reporting.

Thomas L. Robison, 58, of Santa Fe, New Mexico vanished April 21 on the reported excursion, according to the NPS, which released an update on Monday.

NPS personnel were notified on Friday of a body in the river near mile six, the agency announced. Responding rangers recovered the body and transported it to Lees Ferry, a boat launch point at Glen Canyon National Recreation Area, then to the Coconino County Medical Examiner’s Office in Flagstaff.

"Initial information indicates the body is that of missing person Thomas L. Robison," the agency wrote in its statement.

Robison was reported missing last month. His vehicle, officials said, was found abandoned at Lees Ferry.

Autopsy to determine man's cause of death

The county medical examiner was working to officially identity the victim and determine their cause and manner of death, authorities said.

The case remained under investigation on Wednesday by NPS and local authorities.

Natalie Neysa Alund is a senior reporter for USA TODAY. Reach her at [email protected] and follow her on X @nataliealund.