Jason was thought to have drowned after an early morning boat ride with his sister Cheryl Blossom on July 4th. However, his body was discovered much later on. After an autopsy, it was soon discovered that he was shot in the head and died a week later around on July 11th. Jason was also said to have ligature marks, meaning the killer could've possibly tied him up or hold him captive.
Clifford Blossom was revealed to have been Jason's killer, and Mustang as his captor. The motive was that Clifford had been in the drug business and he wanted Jason to inherit it, but Jason wanted nothing to do with it. Clifford killed Jason to stop him from exposing the family business. FP Jones, who had been blackmailed by Clifford, and Joaquin DeSantos later found Jason's body and cleaned up the crime scene in an effort to avoid any attention that'd make it seem to be one of the Southside Serpents. They put Jason's corpse inside of a freezer, then afterward dumped his body in Sweetwater River. Upon this discovery, Clifford murdered Mustang and staged it as a suicide, later hanging himself in the Blossom Maple Barn after being exposed. However, after Penelope Blossom was burnt in a fire caused by Cheryl, she blackmailed her mother by saying she would tell everyone "what really happened in the barn with Daddy", implying that Clifford didn't really commit suicide. FP was jailed for his clean-up role in the murder, and Joaquin left Riverdale so he wouldn't be caught.
|Editor's Note: The characters listed down below are those that were suspected of killing Jason Blossom within the show. The list should not include theories based upon fan speculation.|
- Mustang (captured and tied up Jason)
- FP Jones (cleaned up the crime scene and dumped Jason's body in Sweetwater River)
- Joaquin DeSantos (cleaned up the crime scene and dumped Jason's body in Sweetwater River)
- Hal Cooper (Hal broke into the Sheriff's house and tore up evidence from the murder board)
- Southside Serpents
- Penelope Blossom
- Hiram Lodge
- Hermione Lodge (residing in New York during Jason's time of death)
- Cheryl Blossom (assisted Jason in running away and faking his death)
- Dilton Doiley (claimed the gunshot he fired on July 4th had nothing to do with Jason. He was further eliminated when it was found out that Jason died a week later)
- Geraldine Grundy (claimed to have a gun for protection)
- Polly Cooper (pregnant with Jason's children)
- Jughead Jones (cleared by the police due to falsified alibi)
Images Provided By the Official Tumblr for the CW's Riverdale.