KARACHI: Karachi police on Saturday said they had made a "major breakthrough" in the murder case of Ali Raza Abidi, a former lawmaker who was assassinated in the port city in a murder that has raised fears that the country's financial hub might be bracing for violence in the days ahead. 
Two unidentified gunmen on a motorcycle opened fire at Abidi's car near his residence in Karachi's DHA neighbourhood on Tuesday. He succumbed to his injuries after being taken to hospital. 
"We have got a major breakthrough in the murder case of Ali Raza Abidi," Sindh Police Chief Kaleem Imam told reporters, declining to give more details. 

Kaleem said police had uncovered evidence about the involvement of a foreign group in acts of terrorism in Karachi. 
“Some groups of target killers want to reemerge," he added. "Foreign groups involved in acts of terrorism in Karachi will be taken to task.”
On Friday, Sindh chief minister Syed Murad Ali Shah informed media of a “significant arrest" in Abidi's murder case, confirming local media reports that four suspects had been arrested. 
For over 25 years, the Muttahida Qaumi Movement (MQM) had an iron grip on Karachi, at the time considered one of the most dangerous cities in the world. But a paramilitary crackdown launched in 2013 transformed the port city, sharply bringing down murder and kidnapping rates, while splits within the MQM’s leadership in 2016 broke the grip of party supremo Altaf Hussain. 

In recent days, reports of factional infighting within the MQM have reactivated fears that violence may return to Karachi. 
“The murder of Abidi is most likely the outcome of internal differences,” said senior police officer Raja Umar Khattab. "Incidents over the last couple of days are an indication of more violence in the near future but law enforcement agencies are ready to curb violence.”
A statement issued after a high-level security meeting at the Chief Minister House on Wednesday also cited political reasons behind the murder of Abidi.