A day after a senior labour leader died under mysterious circumstances in police custody in Karachi, a case was registered against the police party which carried out the raid to arrest him, police officials said on Monday.

Babu Karim Jan, the president of the Gadani ship-breaking workers union, had died under mysterious circumstances on Sunday morning, soon after being arrested by police from his residence in Metroville, located in the city's SITE area.

Police claimed that he died of a heart attack when he was arrested while relatives and friends, who held a protest demonstration outside the Karachi Press Club on Sunday evening, said he was killed because of police torture during the raid.

Karachi West SSP Shaukat Khatian told Dawn today that a case has been registered against the raiding police party on a complaint of Jan's family on charges of negligence.

However, the senior officer said no policeman has been arrested so far.

SSP Khatian also disclosed that two attempted murder cases against the deceased labour leader had been handed over to the deputy inspector general of the Crime Investigation Agency (CIA) by the Karachi police chief, AIG Amir Ahmed Shaikh, for investigation purposes.

AIG Shaikh on Monday took notice of Jan's death and ordered an inquiry to ascertain the circumstances and events that led to his death, police officials said.

The city police chief along with DIG West Amin Yousafzai and SSP Khatian visited the deceased's home and expressed his condolences with the family members as well as people gathered in the area.

He informed the family that a team led by DIG CIA Arif Hanif has been established to probe the incident.

According to a police spokesperson, AIG Shaikh promised that a case would be registered against the police party that carried out the raid "if they were found involved in the incident".

Shaikh added that justice would also be provided in the cases registered against the deceased and his son Aminul Haq.

Family members and elders in the area expressed their gratitude to the police for taking action against the police team concerned, according to the spokesperson.