Supporters of the Mutahida Qaumi Movement hold a picture of the party leader Altaf Hussain in Karachi, Pakistan, on June 30.
LONDON -- British police have raided the home and offices of the powerful exiled leader of a major Pakistani political party in connection with the murder of its co-founder and alleged money laundering.
Counter-terrorism officers executed search warrants at two suburban London properties linked to Altaf Hussain. He runs Pakistan’s fourth-biggest political party, the Muttahida Qaumi Movement, from his British base.
Dr Imran Farooq was stabbed and beaten with a brick outside his suburban London apartment block in September 2010.
The party's co-founder Dr Imran Farooq died in September 2010 after being stabbed and beaten with a brick outside the apartment block where he lived in Edgware, on the outskirts of the U.K. capital.
Police recovered a five-inch kitchen knife and the brick at the scene. A $31,000 reward has been offered in the case.
Hussain, 59, has lived in the U.K. since 1992 and is now a British citizen. Hussain and Farooq were both granted political asylum by Britain after claiming that Pakistani authorities were persecuting them for criticizing the government.
Two MQM officials confirmed on Friday that Hussain's properties had been raided by London's Metropolitan Police. The searches occurred on June 18.
In December, officers searched a "business address" in Edgware where "a quantity of money was recovered ... and seized" under British proceeds of crime laws, according to a police statement.
A "further significant sum of money" had been found during the operation on June 18, police said.
In a statement, Metropolitan Police said "an investigation continues into the circumstances in which the money to be at the properties."
Nadeem Nusrat, a London-based spokesman for the MQM, said a sum of money had been seized from Hussain's house.
He added: "There is an ongoing investigation and we will prove this was legitimate money."
Six days after the raids, detectives arrested a man at London's Heathrow Airport on suspicion of conspiracy to murder after he arrived on a flight from Canada, where the MQM have offices in Toronto's Mississauga suburb. The 52-year-old was bailed but has not been charged with any offense.
Dr Farooq Sattar, a MQM spokesman, confirmed that the man questioned on June 24 was a party member.
He said the party was "in shock" about the raids on Hussain's properties.
“Dr Imran Farooq was and is a senior leader of the party and that his murder was a sad death to the party,” Sattar said. “We would want to see the arrest of the real culprit as soon as possible. This is what our stance has been right from day one.
"Our leader has always professed to members of the party is zero tolerance for crime, violence and terrorism and this is what we are known for in Pakistan.”
Metropolitan Police are also investigating comments made by Hussain in the U.K. amid claims they may have incited violence in Pakistan. MQM officials insisted that Hussain had been misquoted.
Hussain was not available for comment on Friday.
The MQM is a secular party which endorses a "philosophy and practicalism." The MQM won 18 out of the 19 national assembly seats in Karachi -- the country's largest city -- in May's election, according to Reuters.
NBC News' Keir Simmons and Wajahat S. Khan contributed to this report.
This story was originally published on Fri Jul 12, 2013 1:19 PM EDT