The father of the junior doctor who was raped and murdered at RG Kar Medical College and Hospital in August 2024 submitted documents to a Sealdah court on Thursday, alleging that his daughter’s viscera samples had been tampered with at a forensic science laboratory in the city.

He is said to have submitted letters to the court from a former employee of the State Forensic Science Laboratory in Belgachia, who allegedly wrote to the parents on May 16 and May 23.

The letters claim that the slain doctor’s viscera samples were tampered with before being sent to the central forensic laboratory for examination, the family said. “The letter has details of the persons who were allegedly involved in tampering with the viscera samples of my daughter and under whose instructions. After receiving the first one in May, we informed the CBI,” the father said.

“Since the CBI did not act on it, I submitted the letters before the Sealdah court seeking a thorough probe into the allegations that have been levelled.”

The father’s move comes weeks after the CBI set up a special investigation team (SIT) to conduct a fresh probe into the rape and murder of the doctor. The three-member SIT was formed on the directions of Calcutta High Court. CBI sources said the investigating officer in the case, Sima Pahuja, has not been included in the new SIT.

On June 17, the SIT visited the Panihati facility where the doctor was cremated. The team later questioned former Trinamool MLA of Panihati, Nirmal Ghosh. Ghosh was among three persons whom the doctor’s parents had accused of rushing the cremation.

“The letters alleged that my daughter’s viscera samples were contaminated, not due to sand and dust particles, but because those who handled the sample did not wear gloves,” the doctor’s mother said. “It needs to be examined whether this was done deliberately.”

In its report, the CBI said hospital and local authorities initially told the parents that the junior doctor was “unwell” and later claimed she had died by suicide. The CBI argued that the initial forensic team collected evidence under this assumption, which affected preservation of evidence.

The doctor’s mother also alleged that the bathroom adjacent to the seminar hall on the third floor of the hospital’s emergency department was demolished “in a calculated move”.

“The health secretary is aware of the demolitions that were carried out even when an investigation was on in the case. It must be probed why the health secretary permitted the demolition work,” she said.