The bail was rejected by the CBI court of Ghanshyam Malik after Sita Soren, the daughter-in-law of JMM supremo Shibu Soren, moved the plea following her private secretary's accusation of beating him up "for being a witness in horse trading during Rajya Sabha election last year".
The Election Commission had countermanded the Rajya Sabha polls in two seats in Jharkhand in the wake of allegations of horse trading and seizure of Rs 2.15 crore in cash.
The CBI had taken charge of the investigation later and conducted raids in the premises of at least 23 MLAs, including Sita Soren's.
The elections were held afresh on May 3 and the then ruling BJP faced embarrassment as their candidate S S Ahluwalia came third in the polls in which Congress and JMM bagged the two seats.