A two-member probe team comprising a DSP and inspector quizzed the boxer. Though the Punjab Police declined to divulge details about the place where the interrogation took place, sources said this was done in Haryana Police Lines near Panchkula.
It was, however, learnt that the boxer refused to give his blood and hair samples to investigator.
Meanwhile, Union Sports Minister Jitendra Singh on Monday said that action would be taken against Singh if the latter was found guilty in the drug scandal that has rocked Indian boxing. The minister said if somebody is implicated or chargesheeted, the government would take an action.
Super heavyweight boxer Ram Singh have already been expelled from the National Institute of Sports after admitting to using drugs along with Singh as 'food supplements', although the latter denied the charges.
The massive scandal was unveiled after 26 kg of heroin worth Rs 130 crore was found at an NRI's flat at Fatehgarh Sahib. A vehicle registered in the name of the Olympic medalist's wife, Archana, was found outside the flat during the raid.
Singh, a former world number one, brought India its first Olympic medal in boxing after winning bronze in the 2008 edition at Beijing.
(With agency inputs)