District and Session Judge S N Singh also sentenced the trio to three years RI under section 201 of the IPC for causing disappearance of evidence of offence.
The two terms will run concurrently.
The woman was burnt to death at her house on June 17, 2010 after her family failed to meet their dowry demands including a motorcycle and a television set.
The three had also destroyed all evidence, including the corpse.
The woman's father had lodged a named FIR against the three charging them of murdering her.
