Special Public Prosecutor Ujjwal Nikam said the court has held them guilty under Section 302 as well as Section 354 of the IPC.
"We prayed today that all the accused be sentenced for life imprisonment and court has awarded the same," he added.
The four men Jitesha Rana, Sunil Bodh, Satish Dulhaj and Dipak Tival have been in jail since their arrest on October 20, 2011, the night of the murder.
Keenan, 24, and Reuben, 29, were attacked outside a popular eatery in Amboli in Mumbai's Andheri on October 20, 2011.
The duo was standing there along with some women friends when the group of men allegedly started harassing the women. Keenan and Reuben were attacked after they tried to stop the harassment.
Keenan died soon after the incident and Reuben died ten days later, on October 30, 2011, in a hospital in Andheri. Keenan worked as a bartender in a five-star hotel.
In January 2012, the police filed a 416-page chargesheet before the Andheri metropolitan magistrate court. In October 2012, the court framed charges, including murder, conspiracy and molestation, against the accused.