The prosecution claimed that Chhota Rajan hatched the murder conspiracy.
A special Central Bureau of Investigation (CBI) court here on Friday acquitted gangster Chhota Rajan in a case related to the 1997 murder of trade union leader Datta Samant for want of evidence.
There was nothing on record to prove that Rajan -- whose real name is Rajendra Sadashiv Nikalje -- hatched the conspiracy, the court said.
The gangster, however, is not likely to be released from jail anytime soon as he is facing trial in dozens of cases in various cities.
Mr Samant, who organised the 1981 textile mill workers' strike in Mumbai, was shot dead on January 16, 1997, while travelling in his Jeep to his office in Pant Nagar in suburban Ghatkopar.
The assailants, who came on a motorbike, fired 17 rounds.
The prosecution claimed that Rajan hatched the murder conspiracy.
But special judge B D Shelke said in the verdict on Friday that nothing was produced to prove that Rajan hatched the conspiracy.
"The material witnesses have turned hostile. They do not support the case of the prosecution. The testimony of other witnesses is not sufficient to prove the charges against the accused," the court said.
In the first phase of the trial, the judgment was pronounced in July 2000.
In the case against Rajan, gangster Guru Satam and Rajan's trusted lieutenant Rohit Verma were shown as absconding accused and their trial was separated.
Rajan was arrested in October 2015 from Bali in Indonesia. Later, the CBI took over all the cases registered against him.