The pathologist at the heart of a decision not to prosecute over the death of a man at the G20 protests is under investigation by the General Medical Council.
Dr Freddy Patel is facing a "fitness to practise" hearing before the GMC.
It is looking at four post-mortem examinations unrelated to the case of Ian Tomlinson in 2009.
Dr Patel was the first pathologist to examine Mr Tomlinson. Two further post-mortem examinations contradicted his.
He said that Mr Tomlinson had died from a heart attack. The two other doctors agreed that the dead man had suffered internal bleeding after some kind of blow.
Mr Patel has been allowed to continue to work during the investigation but has been barred from carrying out Home Office forensic pathology work.
If the GMC concludes that the doctor's fitness was "impaired" he could be either suspended or struck off the medical register.
The GMC investigation is looking at four post-mortem examinations between January 2002 and December 2005 conducted by Mr Patel, two of which involved children.
The public papers in the case allege that Dr Patel's performance was professionally impaired "by reason of misconduct and deficient professional performance".
In the first case, the GMC says that Dr Patel examined the body of a woman, known only as Ms A, in September 2002.
The doctor went to the scene where the partially clothed and decomposing body was found and later wrote that she had died from "opiate poisoning".
The GMC charge sheet says the doctor did not take samples from the body which could have shed further light on the circumstances and that his conclusion was "not fully supported by the evidence available".
Dr Patel allegedly failed to give proper consideration initially to bruises and other marks on the woman's body and the possibility that she may have been asphyxiated.
The manner in which he carried out the examination, the charge sheet alleges, was "irresponsible" and "not of the standard expected of a competent Home Office registered forensic pathologist".
In relation to the post-mortem examinations of two children, the Home Office also alleges that they were not up to the expected standard.
In his statement ruling out a prosecution of a police officer over Ian Tomlinson's death, Director of Public Prosecutions Keir Starmer QC said there were irreconcilable differences between the medical evidence of Dr Patel and two subsequent post mortem examinations.
Dr Patel had been the first to examine the body and concluded that the death was "consistent with natural causes" and the cause of death was "coronary artery disease".
The family and Independent Police Complaints Commission organised a second examination by a second pathologist. He concluded that "blunt force trauma" had partly caused a death by internal bleeding.
This was probably Mr Tomlinson's own elbow hitting his liver after he pushed to the ground by the police officer, said the doctor.
A third post-mortem examination at the request of the Metropolitan Police agreed with the conclusions of the second.
Following the DPP's announcement, Dr Patel issued a statement in which he said: "It would be inappropriate for me to comment whilst my current GMC hearing is ongoing."