ISLAMABAD: Two men were arrested at Karachi airport a few days ago in connection with the killing of MQM leader Imran Farooq in London in September last year.
The suspects are said to be affiliated to a political party.
Officials privy to details told this correspondent that the arrested men had travelled to UK on student visa, stabbed Dr Farooq to death and then flown to Sri Lanka.
They were apprehended soon after they came out of the airport in Karachi after having travelled from Colombo.
It is learnt that they were arrested on a tip from British intelligence and other sources.
Their names have not been disclosed but the sources said that the president, prime minister and security establishment had been informed about the matter.
The sources said the arrests were made by personnel of the country's elite intelligence agency with the help of photographs and videos provided by the British authorities.
The arrested persons have been kept in Karachi and investigation is in progress.
The accused had flown to London in August 2010 and the murder took place on September 16.
London's Metropolitan Police and Scotland Yard had launched an investigation and arrested a suspect who was released later for lack of evidence.
Dr Farooq had co-founded the All Pakistan Mohajir Students Organisation (APMSO), the parent organisation of Muttahida Qaumi Movement, with Altaf Hussain. He was deputy convener of the party, technically next to the MQM chief.
But he left the party in 2009 after developing differences over organisational matters.
The arrest of the suspected killers is considered to be a major breakthrough in the case.