Subang Jaya deputy police chief Supt Abdul Aziz Abdul Majid said the six, who were in their 30s, could help police in the investigation into the case.

The man, a college student in his 30s, was found naked on the ground floor of the condominium at about 8.30pm.

Mr Abdul Aziz said the student was earlier forced to strip and tied up with the two Singaporean women by four Nigerian men who stayed in the unit.

After untying himself, the man tried to make his escape but fell to his death.

Mr Abdul Aziz said the others freed themselves and called the police after the captors fled. -- BERNAMA