He has said this during an interview with 'BBC Sandeshaya'.
This is the first interview Mr. Rajapaksa had given 'BBC Sandeshaya' since he was elected President in 2005.
"Now, Mr. Ranil Wickremesinghe himself charged that Lasantha was killed by a certain individual. Now why can't a probe be held? Is it because the suspects are in the UNP?... I have doubts it is because of that reason," Mr. Rajapaksa has said.
Raising similar doubts with regard to the disappearance of Prageeth Ekneligoda, he has said, "Why aren't the investigations being held? Therefore, we are faced with doubts that the suspects are within the government itself."
Jungle law
Mr. Rajapaksa has also refuted Mr. Wickremesinghe's claims citing that jungle law had prevailed while the Rajapaksa regime was in power.
"It is an blatant lie. It is a lie fabricated to mudsling," he added.
Impeachment
The former President has also stated that Shirani Bandaranayake was impeached in a constitutional manner.
He maintains that since his defeat at the January Presidential election, nothing good has happened to the country and it is moving towards a 'dark age'.
MR admits blunder
However, the former President has admitted that it was wrong to shield certain wrongdoers during his reign.
When asked who these wrongdoers were, he said, "When the daughter of Premadasa - Dulanjalee Premadasa was caught with counterfeit bank notes, I did not allow a proper, legal investigation to be held... I just said this because you all asked me... Now I think it was a blunder."
18th Amendment
Upon being questioned about the 18th Amendment being passed within a matter of few weeks with no debate, Mr. Rajapaksa had declared there was nothing wrong as everything in the country was being decided by the public.
The public is very much aware of what should be retained. What shouldn't. The public should be allowed that, he added.
"Now, all of us are Westernised, Even you are talking from the basis that everything from the West is correct," he had concluded.
(BBC Sandeshaya)