Lal Singh, the girl's father, has been arrested along with his son Rinku. The duo admitted that they had killed Mithun, 20, a graduation student, to safeguard the family's honour.
Mithun's body was recovered on Friday morning in Kajipura village, some 400 km from Lucknow.
"After carrying out preliminary investigations, we interrogated the father and brother of the girl. They confessed to the crime," Inspector Alok Singh told reporters in Bulandshahr.
"After killing Mithun late Thursday, the two had dumped his body in the fields. During investigations, it has also come out that besides the father-son duo, other relatives of the girl were also involved in the crime. Efforts are on to nab all those involved in the killing," he added.
According to police, Mithun and the girl, Anju, were having an affair for the past several months.
