The death of a Atlanta Centers for Disease Control and Prevention researcher whose body was found in the Chattahoochee River last month was due to suicide by drowning, authorities said.

Timothy Cunningham, 35, disappeared Feb. 12, setting off a massive search and a host of conspiracy theories. His body was found by fisherman on April 5. At the time, the Fulton County (Georgia) Medical Examiner's Office said there were no signs of foul play.

This week, the medical examiner released a report indicating that Cunningham's cause of death was drowning and the manner of death was suicide, CBS46 reported. The autopsy report has not been completed at this time.

Cunningham left work in February after telling co-workers he wasn't feeling well. After being reported missing by his parents, police later searched his home and found all of his belongings and his pets. Conspiracy theorists pointed to Cunningham's work with the Centers for Disease Control's chronic disease unit as the reason behind his disappearance.

Authorities said it's unclear how Cunningham first entered the water. His body, found partially submerged in mud on the riverbank, showed no other signs of trauma, according to authorities.