The body of Dr. Forsyth was found May 30, and police initially reported no signs of foul play.
Authorities told ABC that no further information would immediately be released, and they didn't specify if he was shot by someone else or if the wound was self-inflicted.
Richard Forsyth, Dr. Forsyth's brother, told ABC he rejects the idea that the wound was self-inflicted.
"I feel like it is foul play," Jason Musgrave, Dr. Forsyth's brother-in-law, said in a call with the Associated Press. "I feel like it has to have been."
Becker's reached out to the Benton County Sheriff's Office but has yet to receive a response.