According to police, Muttahida Qaumi Movement (MQM) member Fahad Aziz was arrested Saturday night on his way to Orangi town in Sindh province, for his alleged involvement in killings and other crimes, reported the Geo News.
The MQM is a liberal political party of Pakistan and believes in realism. It represents poor middle class.
The arrested man was shifted to a hospital in Karachi after his condition deteriorated, police said.
But his family has claimed that the policemen tortured Aziz, which caused deterioration of his condition.
Hospital sources said Aziz was admitted to the hospital Sunday morning and was being treated in the intensive care unit (ICU).
MQM leader Rauf Siddiqui said police, fearing his custodial death, dumped Aziz in critical condition at the hospital.
Later, an investigating officer and three policemen were suspended. Provincial Information Minister Sharjeel Memon said departmental action would be taken against the suspended policemen after the incident is probed.
The Karachi police claimed there were three pending cases against Aziz, including killing of a policeman.
He would be presented before a judicial magistrate in order to get his remand, police said.
The incident comes a day after the MQM observed a day of mourning in the city against the alleged extra-judicial killings and enforced disappearances of party workers.