Police are investigating concerns over post-mortem tests carried out for a coroner in Oldham.
Dr Khalid Ahmed worked as a histopathologist for the Pennine Acute NHS Trust at the Royal Oldham Hospital - studying how disease affects tissue.
He carried out a number of post-mortem examinations for North Manchester coroner Joanne Kearsley. However, a review has found that some of these examinations gave an "incorrect" cause of death.
Greater Manchester Police said it was "assessing what, if any, criminal offences may have been committed in relation to findings presented to the coroner".

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