How did Alton Sterling end up with gunshots in his chest -- AND in his back?

Did they flip him over and then shoot him on the other side? While he was lying down?

http://www.cbsnews.com/news/alton-sterling-baton-rouge-police-shooting-aclu-questions-lack-of-body-cameras/

Louisiana ACLU executive director Marjorie Esman said in a statement that "questions abound" over the shooting, including why Sterling "was shot to death while he was on the ground and two police officers were on top of him," CBS affiliate WAFB reported.

"Why did the officer shoot -- multiple times -- when Mr. Sterling was already being subdued?" Esman asked. "How did Mr. Sterling end up with gunshots in his chest and his back? What happened to cause both officers' body cameras to fall off during the same incident?"

Esman said she wants to know if the officers were trained in how to properly fasten the cameras. She also said authorities also should investigate whether police could have used some other means of subduing Sterling and "if it was necessary to subdue him at all."

Esman said Sterling was the 122 black person shot and killed by law enforcement in the U.S. this year.