Fadnavis gave this assurance to a delegation, led by Pansare's daughter Smita, which met him at the Vidhan Bhawan seeking a speedy probe into the case.
The CM said that he has instructed the state police to take the assistance of any agency, including foreign experts, to crack the case.
"We are taking all possible help to nab the assailants," he said.
The veteran communist leader was shot in Kolhapur on February 16 after which he succumbed in Mumbai, a few days later.