Former Pakistan Peoples Party (PPP) Senator Faisal Raza Abidi was arrested during an early morning raid at his Karachi residence on Saturday, police said.

Confirming his arrest to Dawn, Jamshed Quarters SP Tahir Noorani said Abidi was taken into custody in connection with the killing of two men who belonged to the Tableeghi Jamaat in Patel Para area of the metropolis a day earlier.

“We have arrested Faisal Abidi for his alleged involvement in the double murder case,” said SP Jamshed Quarters Tahir Noorani.

But in the evening, a top-ranking police officer said that Abidi was “detained” and being investigated in some previous cases of sectarian killings. “He will be released if found innocent,” he said, asking not to be named.

Abidi is now in custody of the police investigation department for interrogation, the police official said.

The murders happened yesterday as armed pillion riders shot the two men dead near the Fatima Bai Hospital and rode away. A spokesman of the outlawed Ahle Sunnat Wal Jamaat (ASWJ) had yesterday claimed that the two victims were their supporters, however, the area SHO said the men killed hailed from Khuzdar and were associated with the Tableeghi Jamaat.

The FIR (379/2016) for the double murder was registered at Jamshed Quarters police station on Friday night under Section 302 (murder) and 7-ATA (anti-terrorism act of 1997) on complaint of the victims’ relative Ghulam Mohammed, said SHO Inam Hasan Junejo. The case was registered against unknown suspects, the official added.

The double murder was followed by killings of three members of ASWJ at Shafiq Mor in North Karachi and a prayer leader in Hyderi Market.

Counter-Terrorism Department official Raja Umer Khattab told Dawn that the same group was involved in all six murders of Friday as the police’s forensic lab report confirmed that the same weapon was used in three separate incidents.

Before his arrest, police and Rangers personnel arrived at the former Senator's residence in the city's New Rizvia Society in at least 10 vehicles at around 2:30am, sources told DawnNews.They searched Abidi's house for about half an hour before taking him into custody.

The firebrand PPP leader had resigned from his Senate seat in 2014 after developing differences with his party.

Abidi, once among the most trusted lieutenants of former president Asif Zardari, was accused of violating party discipline and repeatedly issuing statements in favour of martial law.