Two police personnel, ASI Biju and police driver Ajaya Kumar of Gandhinagar police station near Kottayam, were arrested and suspended for allegedly taking bribe from some of the people accused of killing a 23-year-old man in May this year.
Kevin P Joseph, a Dalit Christian, was abducted on May 27 by a gang allegedly engaged by his fiancee's family, who were opposed to their move to marry.
His body was found in a river in Kollam district a day later.
Police had said the ASI and the driver, on a night patrol on May 26, had intercepted a car being used by the gang after noticing that its number plate was hidden.
However, the two allowed the vehicle to proceed after taking a bribe of Rs 2,000, they had said.
The action against the two police personnel was taken as the trial in the case is set to begin at a court here.
Joseph's relatives had alleged that he was tortured and killed two days after he and his fiancee filed a joint application for registration of their marriage at a sub-registrar office near here.