A special court today dismissed the plea of an accused seeking to summon former Prime Minister Manmohan Singh as defence witness in a coal scam case. Special CBI Judge Bharat Parashar rejected the plea saying the application was "vexatious" and it was apparently moved to delay the trial. <br/><br/>The court also rejected the plea of the accused R S Rungta, Director of Jharkhand Ispat Pvt Ltd (JIPL), seeking to summon ex-Minister of State for Coal, Dasari Narayan Rao, as a witness in his defence. The case pertains to alleged irregularities in allocation of North Dhadu coal block in Jharkhand to the firm.