The Office of State Pathologist Professor Marie Cassidy has been plunged into crisis after her deputy, Dr Khalid Jaber, launched an extraordinary attack on her.
In a series of letters, seen by the Irish Independent, Dr Jaber also accused Prof Cassidy of making "insulting" comments in a newspaper article.
Lacking a certification in forensic pathology - a sub-speciality of pathology that focuses on determining the cause of death by examining a corpse - is not a barrier to a pathologist giving expert evidence in trials. However, respected bodies such as the American Board of Pathology say having it is an advantage. Prof Cassidy declined to comment on Dr Jaber's criticisms. The Department of Justice also declined to answer questions about Dr Jaber's claims.
However, Prof Derrick Pounder, who has been professor of forensic medicine at the University of Dundee for the past 27 years and was the external assessor on the interview board which appointed Prof Cassidy, said she had shown her competence to be state pathologist through her work over the years.
He added it would be "an utter waste of time and government money" for Prof Cassidy to have to seek such certification at this stage of her career.
Scottish-born Prof Cassidy (54) has headed up the State Pathologist's Office since 2004, and is assisted by two deputies, Dr Jaber and Dr Michael Curtis.
In a letter sent to the RCPI earlier this year, and another more recent one to the DPP, Dr Jaber questioned Prof Cassidy's qualifications.
He described Prof Cassidy as "only a general pathologist with interest in forensic pathology, and not a professional who holds specific credible certification in the sub-speciality of forensic pathology". Such certification is not available in Ireland.
Dr Jaber, whose certification was awarded by the American Board of Pathology, said he had raised the issue previously with Justice Minister Alan Shatter.
He said Prof Cassidy should not be seen as the "benchmark standard", while she lacked this certification.
The Irish Independent asked the Department of Justice to release details of Prof Cassidy's qualifications, but it refused.
However, in an interview in 2001, Prof Cassidy acknowledged while she then had no specific qualifications in forensic pathology, she had "learned the hard way, on the job".
Dr Jaber said Dr Curtis also lacked certification in forensic pathology. The department also declined to release details of Dr Curtis's qualifications and he did not respond to a request for comment. However, Prof Pounder said Dr Curtis is "certainly competent to hold the post".
In the letter to the RCPI, Dr Jaber directly questioned the suitability of Prof Cassidy's appointment. "The lead person in charge of the national forensic pathology service must be certified in forensic pathology distinctly," he said.
Dr Jaber also took exception to a newspaper article in which Prof Cassidy predicted her successor would have to come from outside the country, unless the Medical Council recognises forensic pathology as a profession and training is established.
In the letter, he described this statement as "insulting" and said that some foreign-born pathologists working here "are Irish citizens; and are entitled to be considered for this job".
The Royal College of Pathologists, which certifies pathologists in the UK, said it did not set any guidance on the qualifications needed for a pathologist to act as an expert witness in a criminal trial.
A spokeswoman for the American Board of Pathology said: "There would be no legal requirement for a pathologist giving evidence in a criminal case to hold certification in forensic pathology."
However, she added: "It would be our opinion that it would be an advantage to all individuals to hold certification."