A Denham Springs man facing a count of second-degree murder pleaded not guilty by reason of insanity Thursday in a case involving a body found shot in the head and floating in the Blind River Canal in 2013.

In a brief hearing, Joshua M. Mitchell changed his plea from not guilty in the 21st Judicial Circuit Court in Livingston before Judge Elizabeth Wolfe.

Detectives have said they believe Mitchell shot 26-year-old Brandon Steele Parnell while they were on a highway in the Denham Springs area in February 2013. They think he then drove to St. James Parish and dumped the body in the canal near U.S. 61 just north of Gramercy. The body later was spotted by a fisherman.

In March 2013, investigators in a helicopter spotted Parnell’s van at a home where they found and arrested Mitchell. The Livingston Parish Sheriff’s Office has alleged Mitchell tried to clean the van to remove evidence.

He also has been charged with obstruction of justice by tampering with evidence, possession of a firearm or carrying a concealed weapon by a convicted felon, and failure to register as a sex offender.