The police had arrested four persons for brutally thrashing Salim Shaha, 34, a member of the BJP's Katol unit, on July 12 and sent the meat he was carrying to a forensic laboratory.
The lab report was "positive", i.e. it was beef, Superintendent of Police (Nagpur rural) Shailesh Balkawde said on Saturday.
Police will initiate further action against Shaha in accordance with the law, he said.
Meanwhile, the Nagpur (rural) unit president of the BJP, Rajiv Potdar, expressed shock at the findings.
It was shocking that Shaha has been found to be carrying beef that day, Potdar said, adding he would be dismissed from the party.
Stern action should be taken against him according to the law, but people must not take law in their own hands and resort to violence in such cases, Potdar said.
Shaha's mother had claimed that he was the head of the BJP's Katol tehsil minority morcha, while local leaders said he was a party member.
The incident of thrashing had drawn strong condemnation from the ruling BJP's coalition partner Shiv Sena, besides the opposition Congress and Nationalist Congress Party.
However, the BJP had sought to play it down, calling it a "stray" incident.
Shaha, the resident of Katol town in Nagpur district, was returning home on his motorcycle when five-six men accosted him at a bus stop on July 12 in Bharsingi village on suspicion that he was carrying beef and assaulted him.
Four men -- Ashwin Uike (35), Rameshwar Taywade (42), Moreshwar Tandurkar (36) and Jagdish Chaudhari (25) -- were subsequently arrested and booked under IPC section 326, pertaining to voluntarily causing grievous hurt.
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