NYPD Detective Ardisano stating "No Head Trauma"

Three weeks after the Medical Examiner declared the cause of death "blunt force trauma to the head with skull fractures and brain injuries", Detective Ardisano of the 109th Precinct stated:

"Oh no, there was no head Trauma" (1:53)

and that the manner of death was "natural" (2:06)

It appears the Ardisano was "not in the loop" of the conspiracy to hide the circumstances of Sheu's death, and that records he consulted were false. 

The question is this: who is responsible for creating the false report that Ardisano cites in this conversation?

How is it possible that three weeks after the Medical Examiner reported that the cause of Sheu;s death was "blunt force trauma to the head" and the manner "undetermined" (which triggers an immediate homicide investigation), that the NYPD's reports contradict the M.E.'s findings?

Prior to the M.E.'s determination of June 29th, there should have been NO determination of the cause or manner of death listed in the NYPD records, and after the M.E.'s determination, the NYPD's records must conform to his.

Clearly the motivation for planting false reports can only be to avoid an investigation.

Who planted the false reports?

Why has the NYPD not investigated this alteration of evidence, despite letters to Commissioners Kelly and Bratton specifically demanding an investigation?