London police free divisive Pakistan politician Altaf Hussain, continue money-laundering probe

Supporters of the Muttahida Qaumi Movement, or MQM, one of Pakistan's major political parties, attend a sit in protest condemning the arrest in London of its leader, Altaf Hussain, in Islamabad, Pakistan, Wednesday, June 4, 2014. British police arrested one of Pakistan's most well-known and divisive politicians Tuesday on suspicion of money-laundering, sparking fears of violence in his power base of Karachi where businesses closed early and residents rushed home. (AP Photo/Shakil Adil) (The Associated Press)

Supporters of the Muttahida Qaumi Movement, or MQM, one of Pakistan's major political parties, attend a sit-in protest condemning the arrest in London of its leader, Altaf Hussain, in Islamabad, Pakistan, Thursday, June 5, 2014. British police arrested one of Pakistan's most well-known and divisive politicians Tuesday on suspicion of money-laundering, sparking fears of violence in his power base of Karachi, where businesses closed early and residents rushed home. (AP Photo/Fareed Khan) (The Associated Press)

Pakistani security officials examine the site of a blast in Karachi, Pakistan, Thursday, June 5, 2014. Police and paramilitary officials cordon off the area after a bomb blast that left at least one dead and five injured, police said. (AP Photo/Shakil Adil) (The Associated Press)

London police say they have conditionally released one of Pakistan's best known politicians but still are investigating him for alleged money laundering.

Saturday's release on bail of Altaf Hussain came four days after his arrest at his northwest London home. The 60-year-old spent three days in custody at a hospital receiving previously scheduled medical treatment, then faced police interrogation Friday.

The Metropolitan Police say Hussain must return for more questioning next month.

Hussain is the long-distance leader of the dominant political party in Karachi, Pakistan's largest city. His Muttahida Qaumi Movement frequently has been accused of threatening and killing political opponents. His party denies this.

Police say they are investigating the source of approximately 400,000 pounds ($675,000) seized last year during searches of London properties, including Hussain's home.