FRUITLAND — Preliminary autopsy results of the Native American man found dead earlier this week in the San Juan River identify him as Kirtland resident Anderson Thompson, according to the FBI.

Thompson's body was found fully dressed Tuesday afternoon about a quarter mile from Nenahnezad Chapter House in Fruitland on the Navajo Nation.

The autopsy results determined the 33-year-old man drowned, FBI Media Coordinator Frank Fisher said.

No other trauma was detected, he said.

The man's condition indicates he wasn't in the river more than about one or two days, Fisher said. The FBI doesn't know where the man entered the river, Fisher said.

Toxicology results will likely determine if the man was drunk or under the influence when he died, Fisher said.

San Juan County Sheriff's Office deputies and Navajo Nation police responded to the scene before authorities determined the body was on the reservation, said Beth Utley, the Sheriff's Office public information officer.

Utley said the county's response was standard procedure.

A nearby county helicopter on a routine fight also responded to the scene, she said.

At 3:09 p.m., on-scene authorities called the FBI.

Dan Schwartz covers government for The Daily Times. He can be reached at 505-564-4606 and dschwartz@daily-times.com. Follow him @dtdschwartz on Twitter.