The NCP leader had levelled fraud allegations against Mr Wankhede.
A sessions court in Maharashtra has directed the Washim police to conduct an investigation into the alleged remarks made by Nationalist Congress Party leader Nawab Malik against Sameer Wankhede, the former Mumbai zonal director of the Narcotics Control Bureau.
The sessions court in Washim district passed the order on Tuesday on a complaint filed by Sanjay Wankhede, the cousin of Indian Revenue Service (IRS) officer Sameer Wankhede.
Sanjay Wankhede had in his complaint sought an investigation against the former Maharashtra minister for making defamatory and false remarks on the caste certificate and caste of Sameer Wankhede and their entire family.
He had sought a probe against Mr Malik under the Scheduled Castes and the Scheduled Tribes (Prevention of Atrocities) Act.
Additional sessions judge H M Deshpande directed the Washim police to investigate the matter and submit a report.
The court said the police have not taken any action despite a complaint sent to them in November 2021.
"Considering the allegations made in the complaint, an investigation as prayed by the complainant is necessary in the present matter," the order said.
Sanjay Wankhede claimed he had first written to the Washim police seeking for a case to be registered against Mr Malik. When the police did not take any action, he filed a private complaint with the sessions court seeking a probe against Mr Malik.
"Considering the allegations made in the complaint and documents filed on record, more particularly the caste certificate, it certainly discloses a cognisable offence which is necessary to be investigated by the police," the court said in its order.
The Enforcement Directorate arrested Mr Malik in February this year in a money laundering case. He is in judicial custody and currently undergoing treatment at a hospital here.
The NCP leader last year alleged that Sameer Wankhede had submitted forged documents to obtain his caste certificate.
The IRS officer then refuted the allegations and said Mr Malik was targeting him as the NCB had arrested the NCP leader's son-in-law in a drugs case.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)