Three men were arrested while attempting to sell two leopard skins in Ghatkopar, on Saturday.
The accused were identified as Shailesh Shinde (30), Vikram Raju More (33) and Sandesh Renuse (34).
The men, from Mahad taluka in Raigad district, had arrived in the city on the same day to sell the skins.
The police said that More and Renuse, who are farmers in Mahad, were in financial crisis and had decided to make money by killing leopards and selling their skins.
Renuse had killed a leopard last year. He killed another leopard in Phulkewadi jungles near Mahad, added the police.
"The accused wanted to sell the skins for Rs 2.5 lakh. The accused claimed that they were searching for interested parties," said Prabhakar Kamble, sub inspector of the Pant Nagar police station.
The Pant Nagar police have registered a first information report against the accused under the Wildlife Protection Act, 1972.
They have been remanded to police custody until Monday.