According to the police, jail officials and CRPF were keeping a vigil on the roads surrounding the jail following recovery of some rubber balls containing 'ganja' from the compound thrown by two persons a week ago.
Two persons, a 16-year-old boy and a 23-year-old student of BBM course in a city college, were arrested by the CRPF personnel when they were about to throw the balls from Balasundaram Road side, police said.
Three balls, containing 'ganja', sim card and cell phone battery were recovered from them.
They are being questioned on the source of supply and receivers of the contraband, sources said.