The London based leader of the Muttahida Qaumi Movement (MQM), Altaf Hussain, who was arrested three days ago by Scotland Yard from his home in north London on suspicions of money laundering was released on bail today.

Arrested last on June 3 Mr. Hussain was transferred to a hospital for a series of health checks. He was interrogated for seven hours yesterday before being released on bail today. Investigations are however continuing into his case and Mr. Hussain is to report back to the police in July.

According to media reports, his release was wildly celebrated by his supporters in Karachi, the power base of the MQM. Violent protests had broken out in the city after his arrest.

The 60-year old leader moved to London in 1990 and subsequently took British citizenship, claiming that there were threats to his life in Pakistan.

After his release, Mr. Hussain spoke to his supporters over the phone, thanking and congratulating them, and asking them to wind up their protests.

Bloomberg reports that the U.K. police found £400,000 that was not accounted for.

The case against Mr. Hussain is part of a probe that was launched after the killing in London of Imran Farooq, a senior leader of the MQM.

The MQM website reported the release of Mr. Hussain, saying that the party was grateful that he was “afforded the highest standards of medical care.”

It adds: “As the leader of a democratically elected party, Mr. Hussain understands that this on-going investigation is part of due process and completely normal behaviour in a democratic country.”

The MQM claims to represent the interests of the mohajirs, the Urdu-speaking Muslim refugees who migrated from India after Partition. They quickly rose to the top in the government and bureaucracy in Karachi, only to have their dominance curbed when the Pakistan government introduced quotas in government services for locals. The sense of resentment amongst the mohajirs created the MQM and fuelled its growth.