Family and relatives of Kirpal Singh, an Indian prisoner who was found dead under mysterious circumstances at a Lahore jail after being held for more than 20 years in Pakistan on spying charges, staged a protest on Tuesday at the Indo-Pakistan Attari border.

Dalbir Kaur, the sister of Sarbajit Singh, another Indian prisoner who was killed in an attack by fellow prisoners at Kot Lakhpat jail in Lahore, was also seen protesting along with Kirpal's relatives. They raised anti-Pakistan slogans near the Integrated Check Post (ICP) at Attari border.

"My brother Kirpal has been murdered just like Sarabjit was earlier. The Pakistani jail authorities are responsible for his death," Jagir Kaur said during the protest.

Kirpal, 50, who hailed from Gurdaspur district in Punjab had allegedly crossed into Pakistan in 1992 and was arrested. He was later convicted for a bomb blast. Though he was sentenced to death initially, the sentence was later commuted to a 20-year jail term by a Pakistan court under suspicious charges that were never proven.

Jagir Kaur said while the family could not campaign for his release due to severe financial constraints; no politician came forward to support his case.