LAHORE, Pakistan (AP) — Pakistani authorities are investigating the shooting death of a man who had been acquitted of killing accused Indian spy Sarabjit Singh in a Lahore prison in 2013, a police official said Sunday.

Pakistan has previously accused India’s intelligence agency of being involved in killings inside Pakistan, saying it had credible evidence linking two Indian agents to the deaths of two Pakistanis last year.

The man who died in the eastern Pakistani city of Lahore on Sunday was Amir Tamba. He was a suspect in the death of Sarabjit Singh, an Indian national who was convicted of spying in Pakistan and handed a death sentence in 1991.

But Singh died in 2013 after inmates attacked him in a Lahore prison. His fate inflamed tensions between the two South Asian nuclear-armed rivals.

Tamba and a second man went on trial for Singh’s death but were acquitted in 2018 due to lack of evidence.