ISLAMABAD: The National Accountability Bureau (NAB) Peshawar has summoned the Pakistan Tehreek-e-Insaf (PTI) Chairman Imran Khan and NAB Lahore former Punjab chief minister and PML-N President Shahbaz Sharif.Imran has been summoned in the helicopter case on July Continued from Page 1218 and Shahbaz in Pak Power case on July 16.Chairman NAB Justice (R) Javed Iqbal had directed the NAB KP director general in February to conduct an inquiry into alleged use of the former chief minister’s official helicopter by Imran.He was directed to ascertain how the chief minister handed his official helicopter over to someone else and find out if the same practice was also committed by others.The former Khyber Pakhtunkhwa government spent millions of rupees on Imran’s use of the provincial government’s helicopter. Earlier, the NAB had summoned former KP chief minister Pervez Khattak in the case.