Special Judge (anti dacoity) Sanjay Kumar convicted the SP MLA and his brother Laxman Singh yesterday after which they were sent to jail.
The quantum of punishment is likely to be pronounced on Monday.
According to the prosecution, Kishan was attacked and killed by Kaptan and his brother on April 20, 2002.
An FIR was lodged against Kaptan, Laxman and nine others in this connection.
An MP or MLA faces disqualification on conviction by a court in a criminal offence with a jail sentence of two years or more.