LAHORE: Indian spy Sarabjit Singh passed away in Lahore’s Jinnah Hospital on late Wednesday night, DawnNews reported.

Sarabjit Singh, who was sentenced to death 16 years ago on espionage charges, died at 1:00 am local time (2000 GMT) after lying in a comatose state for the last five days, a senior doctor at Jinnah hospital in Pakistan's eastern city of Lahore told AFP.

The Principal of Allama Iqbal Medical College, Prof Dr Mahmood Shaukat, confirmed his death.

He said that Sarabjit’s body had been sent to the mortuary after he was removed from the ventilator. He said the postmortem would be performed on Thursday.

Moreover, he said the condition of the patient was already critical because of low Glasgow Coma Scale (GCS).

Another doctor treating Sarabjit said he suffered a massive heart attack which led to his death. He said the surgeons made an attempt to insert a pacemaker to bring the patient back to life, but to no avail.

The doctor who spoke to AFP said arrangements were under way for an autopsy.

Singh's lawyer Owais Sheikh also confirmed the death and said that his body “has been moved to the hospital mortuary”.

A convicted Indian spy on death row, Singh was attacked on April 26, Friday by two inmates in Kot Lakhpat jail when he left his barracks for a stroll.

He suffered severe injuries in the head whereby he was admitted to the Intensive Care Unit (ICU) of the Lahore’s Jinnah Hospital where a medical board comprising senior neurosurgeons treated him.

According to a report published in Dawn earlier, the prisoners assaulted Singh with bricks and other blunt weapons and left him seriously injured. A medical board was constituted for his treatment and he was put on a ventilator.  His family members meanwhile had flown in from India.

His family insisted he was a victim of mistaken identity and had inadvertently strayed across the border while drunk.

Four members of Singh's family — his wife, two daughters and his sister — who travelled to Lahore on Tuesday have since returned to India, according to the Press Trust of India.

Earlier, Sarabjit’s sister Dalbir Kaur told newsmen at Wagah border that she was returning to India to take care of Sarabjit’s children.

She demanded that Pakistan should hold an inquiry as to how Sarabjit’s security was compromised and he was subsequently attacked with bricks and iron rods.

“If the attacked was planned by the government itself then there is no need for an inquiry. But if Sarabjit was attacked without the knowledge of the authorities then an inquiry is definitely needed.”

Sarabjit’s lawyer Awais Sheikh said he would file a fresh petition in Lahore High Court (LHC).

The attack made front-page news in Indian newspapers, with Indian television stations running frequent updates on his condition and Prime Minister Manmohan Singh described it as a “very sad incident”.

A senior official in Delhi had said diplomats from the high commission in Islamabad were not allowed to visit Singh in hospital, and had also complained about a lack of information on the prisoner's condition.

The Pakistan foreign ministry however insisted Indian diplomats in Lahore were given access to Singh on two occasions.

Singh had illegally crossed into Pakistan on Aug 29, 1990. He was arrested on charges of carrying out four bombings in Faisalabad, Multan and Lahore which killed 14 Pakistani citizens. He was later sentenced to death.

Singh’s security was tightened after the recent execution in India of Afzal Guru, who was convicted of involvement in the 2001 terror attack on the parliament.

Singh’s mercy petitions were rejected by courts and former President Pervez Musharraf.

The outgoing Pakistan Peoples Party (PPP)-led government put off Singh’s execution for an indefinite period in 2008.

The Human Rights Commission of Pakistan (HRCP) condemned the attack on Singh as a “dastardly act” and called on the government to make a thorough inquiry into the matter and punish the guilty persons.

“The authorities have obviously failed to do their elementary duty” of providing him safety and security, the commission said in a statement.