The Congress on Thursday questioned Prime Minister Narendra Modi's silence on the allegations of a scam against BJP president Amit Shah's son, and demanded that Shah step down in order to facilitate a probe.Addressing a press conference in Panaji at the party state headquarters All India Congress Committee spokesperson Priyanka Chaturvedi also said that the functioning of Jay Shah co-owned company, Temple Enterprise Pvt. Ltd allegedly mirrored the standard operating procedure of a shell company and must be investigated as part of the Prime Minister's campaign against shell companies."For the sake of probity, for the sake of what Modi stood for. If there is nothing to hide, what stops Amit Shah from stepping down and allowing a probe to happen; a probe which will perhaps clear his son. But we must always remember, Caesar's wife should be above suspicion," Chaturvedi told reporters."Why is it that the Prime Minister is protecting him? What stops the PM from seeking accountability from a person he is closest to? And someone who perhaps compromises his entire branding of zero tolerance to corruption," she said."Why, when the Prime Minister is saying he is running after the shell companies and shutting down shell companies, isn't this a standard operating procedure of a shell company and why should not that come under investigation?" she also said, accusing the central government of running away from an investigation.An online portal alleged that Jay Shah's company's turnover grew from Rs 50,000 to Rs 80.5 crore in a 2015-16, within one year, after obtaining an unsecured loan from a non banking financial institution.