Out to attend a birthday party, three people, including a woman, were shot dead by unidentified assailants in the parking lot of a hotel in Panchkula, Haryana, police said on Monday.
The incident took place on Sunday night.
The victims have been identified as Vicky and Vipin, both residents of Delhi, and Nia from Hisar, said Inspector Sombir, Station House Officer, Pinjore.
"The three had come to attend a birthday party when the incident took place," Assistant Commissioner of Police (Crime), Panchkula, Arvind Kamboj said.
Vicky, aged around 30, had a criminal background and was involved in some cases, he said.
"We are scanning CCTV footage and gathering other clues," he added.
The motive behind the killing was not immediately clear. Police have not ruled out old enmity.