CBS News reported several of Shapiro's actions while serving as PA AG are receiving renewed attention, including the death investigation of Ellen Greenberg -- a Philadelphia teacher stabbed 20 times -- 10 times in the back -- in 2011.

While first ruled a homicide, local police scoffed at the conclusion ... arguing it couldn't be murder because the door was locked from the inside and her fiancé -- who said he broke down the door to find her -- had no defensive wounds. The medical examiner ultimately changed his determination and called it a suicide.

Lots of folks were outraged ... how could someone commit suicide by stabbing themselves repeatedly in the back and the head?

Flash forward to 2022 ... Shapiro -- then PA's AG -- and his office reviewed the case and doubled down on the suicide determination. But there were unverified rumblings Shapiro had a conflict of interest -- a relationship with Greenberg's fiancé's family -- so the case was referred back to the Philadelphia DA.

Now, some are pointing to Shapiro's handling of the case as a reason he was passed over for the VP candidacy ... with Kamala Harris choosing Minnesota Governor Tim Walz instead.

Ellen's family has repeatedly expressed outrage over the official cause of death ... with her mother Sandra publicly blasting Shapiro when he first announced he was running for governor ... claiming he did little in the four years as AG to properly handle the case.

Worth noting ... CBS News also mentions Shapiro's office allegedly mishandling a sexual harassment allegation against an aide as another reason he didn't get the gig.