Stephen Smith's Family Lawyer Says It Was Clearly Murder, and Autopsy Will Prove It

The attorney for the family of the 19-year-old who was found dead years ago near Alex Murdaugh's home is telling us exactly why he won't accept the simple hit-and-run theory surrounding his death -- he believes it's cold-blooded murder.

Attorney Ronnie Richter joined us on "TMZ Live" Tuesday, making it clear Stephen Smith's mother is determined to get justice for her son, and the first step is exhuming Stephen's body for clues.

Ronnie ticked off a number of facts that clearly point to murder -- Stephen's body from the torso down had no injuries, there were no car parts found at the scene, his shoes were still on, he supposedly walked 3 miles in the dark without ever using his cell phone ... and there's a lot more.

As for looking into any possible Murdaugh connection, Ronnie isn't jumping to any conclusions the disgraced lawyer's family was involved ... although he's keenly aware the case was reopened as authorities were deep into the Murdaugh murder investigation. By the way, Stephen's body was found near the Murdaugh home.

Murdaugh's surviving son, Buster, knew Stephen and there have been rumblings in town the 2 had some sort of relationship. Buster released a statement Monday dismissing the rumblings and denying any involvement in Stephen's death.