Rajasthan Chief Minister Ashok Gehlot's elder brother Agrasain Gehlot has been asked to join investigation in an alleged money laundering case linked to the fertiliser export scam that took place between 2007 and 2009. The Enforcement Directorate has summoned him for questioning on Wednesday. "Agrasain Gehlot has been asked to appear before the agency officials in Delhi tomorrow morning," sources in ED said.