In a letter to Cabinet Secretary P K Sinha, Home Secretary Rajiv Mehrishi has said that finding Prasad's replacement will not be easy and changing the officer, who was recently in news for allegedly 'tutoring' a witness, will set the clock back by almost three months.
While seeking the three-month extension, he also said that the probe is "highly sensitive" and the report may be discussed in Parliament.
The department of personnel and training has then processed the request for Prasad's extension which was approved by the prime minister for only two months till July 31.
Prasad, a 1983 batch IAS officer of Tamil Nadu cadre, was due to retire on May 31. The government has recently appointed Maharashtra cadre IAS officer Bipin Bihari Mallick as his replacement.
In the aftermath of the controversy surrounding the issue of missing papers from the file dealing with the filing of affidavit in Ishrat Jahan case, the Home Ministry had ordered an enquiry by Prasad on March 14, this year. The panel has submitted its report on June 15.
"Since this is highly sensitive enquiry and there is all likelihood that the report will be discussed and analysed in several forums including, perhaps, in Parliament.
"It is imperative that the enquiry may be completed by B K Prasad himself, because to change the enquiry officer at this stage will set the clock back by almost three months.
Also, finding a replacement will not be easy; the officer doing this enquiry has to be fair-minded and with experience of having worked in the MHA," Mehrishi has said in the letter written on May 3, which also cited Prasad's retirement in that month-end.
Considering these circumstances and the public interest involved, the Home minister has approved the proposal for granting extension in service to Prasad for a period of three months, beyond May 31, 2016, i.e. up to August 31, 2016, the Home secretary had said and requested approval of the competent authority.
Ishrat Jahan, 19, and three others were killed in an alleged fake encounter in Gujarat in 2004. The Gujarat police had then claimed those killed were LeT terrorists and had gone there to assassinate the then chief minister Narendra Modi.
The papers, which disappeared from the Home ministry, include the copy of an affidavit vetted by the then attorney general and submitted in the Gujarat high court in 2009 and the draft of the second affidavit vetted by the AG to which changes were made by the then Home Minister P Chidambaram.