Ramesh (22) and Poonam (18) were allegedly murdered by the girl's family on April 2 after they were found in a compromising position at the latter's home.
Five persons were arrested earlier in connection with the case while the girl's brother Raman and his friend Sonu, who were absconding, were arrested last evening, police said.
According to Raman's statement given to police, he saw the duo at the room on the night of April 2 and locked them from outside, they said.
The girl's father, Tara Chand and her relatives Ram Niwas, Raj Kumar Shashi, Surendra have already been arrested, they added.