He also said the principal Opposition party, which has been raising concerns over institutional independence, needs "serious introspection".

"This is an irrefutable evidence of what the Congress did to our investigative agencies. Those who have recently shown a belated concern for institutional independence should seriously introspect as to what they did to the CBI when they were in power," Jaitley said in a Facebook post.

He was referring to the judgement delivered by special Central Bureau of Investigation (CBI) court in the politically sensitive Sohrabuddin Sheikh-Tulsiram Prajapati and Kausar Bi's alleged encounter killings case.

The court acquitted all the 22 accused saying "witnesses and proofs provided were not satisfactory".

The court also said it was targeted "to act upon a script" and "anyhow implicate political leaders".

Jaitley slammed Congress President Rahul Gandhi for his veiled dig at the Narendra Modi-led Central government over judicial verdicts in the case, saying "no one killed...they just died".

"The Congress President on the day of the judgement raised the issue 'that nobody killed Sohrabudin'. It would have been more appropriate if he had asked the right question, namely who killed Sohrabudin case investigation, he would have got the right answer," he said.

He said the Special CBI Judge, Mumbai, who deals with CBI cases has acquitted all the accused in the Sohrabudin case.

"More relevant than the order of the acquittal is the observation of the judge that in the investigation, from the very beginning, the investigating agency did not investigate the case professionally in order to find out the truth but to divert it towards certain political persons," he said.

The senior BJP leader also shared a letter written to then Prime Minister Manmohan Singh on September 27, 2013 as the Leader of Opposition in Rajya Sabha about the alleged politicisation of the investigation in the Sohrabudin, Tulsi Prajapati, Ishrat Jahan, Rajinder Rathore and Haren Pandya cases.

"Every word of what I have said in the letter, over the next five years, have proven to be true," he said.

Special CBI Judge S.J. Sharma in a strong indictment of the CBI had said that the entire investigation was targeted to act upon a script to achieve the said goal and in the process of its zeal to anyhow implicate political leaders.

"It clearly appears that the CBI was more concerned in establishing a particular preconceived and premeditated theory, rather than finding out the truth," said Special Judge Sharma.