A special court for CBI cases hereon Thursday sentenced a Railway Protection Force's (RPF) sub-inspector to three years' imprisonment for accepting a bribe for Rs 4,500 in 2013.Special judge A S Sayyad convicted Laxman Kushwah, the accused, under the Prevention of Corruption Act.As per the Central Bureau of Investigation, Kushwah demanded Rs 10,000 from a tout to allow him to sell tickets illegally at a railway reservation centre at Girgaum in south Mumbai.Kushwah assured the complainant that on the other hand, if he paid the bribe, an earlier case registered against him and his employee will be closed.After the tout approached the CBI, the agency's Anti- Corruption Unit laid a trap and arrested Kushwah in November 2013 while he was accpting the bribe.Special public prosecutor Sandeep Singh examined 14 witnesses during the trial.