The wife and stepson of a Ku Klux Klan leader found fatally shot next to a river in eastern Missouri have been charged over his death.

Malissa Ann Ancona, 44, and her 24-year-old son, Paul Edward Jinkerson Jr, were charged with first-degree murder, tampering with physical evidence and abandonment of a corpse in the death of Frank Ancona. Both have been jailed without bond.

A probable cause statement alleges that Ancona, 51, was fatally shot in his sleep on Thursday at his home in Leadwood, Missouri. St Francois County Sheriff’s Department detective Matt Wampler wrote that after the shooting, Ancona’s body was taken in Jinkerson’s vehicle to an area near Belgrade, Missouri.

A family that was fishing found the body of her husband, 51-year-old Frank Ancona, on Saturday, along the Big River near the tiny town of Belgrade.

An autopsy conducted on Sunday revealed he died of a gunshot to the head. 

Mallissa Ancona has been charged over her husband’s murder. Photo: AAP

The Park Hills Daily Journal said investigators placed yellow police tape around Ancona’s home in Leadwood Saturday, believing he was killed there.

His safe had been broken into and the contents removed. Several of Ancona’s guns were missing, police told the Daily Journal.

Ancona was reported missing on Friday after his employer told Leadwood police that Ancona had not shown up for work for two days.

Prior to the discovery of Ancona’s body, Malissa Ancona told police her husband had left the state on a delivery job.

She said he planned to file for divorce when he returned.

Ancona called himself an imperial wizard with the Traditionalist American Knights of the Ku Klux Klan.

A website for the group includes an image of Ancona in a white hood and robe standing in front of a burning cross.

The website describes the group as a “White Patriotic Christian organisation that bases its roots back to the Ku Klux Klan of the early 20th century”.