The Central Bureau of Investigation (CBI) on Monday said it has booked 19 persons, including six Customs officials posted at the Trichy International Airport, on charge of involvement in the smuggling of gold and other valuables.The CBI has registered cases against these persons under the Indian Penal Code and Prevention of Corruption Act for alleged criminal conspiracy, public servant taking undue advantage, influencing and bribing public servants and abetment to crime.Among those named in the FIR filed in Madurai are senior Customs officials like Assistant Commissioner M. Venkatesulu, two Superintendents S. Ramakrishnan and Kalugasalamoorthy, and three other Customs officials.The CBI received reliable information that Customs officials at the airport were allowing smugglers to bring in valuables without payment of duties from Sri Lanka, Malaysia, Singapore and other countries.The CBI conducted surprise checks on August 5 and 6 at the airport and noticed that people waiting near the airport's arrival gate had paid money to some passengers.These passengers later returned with goods loaded on trolleys. The accused Customs officials allegedly did not open all the baggage for checking.The CBI officials seized Rs 904,000 kept in a safe allegedly belonging to a Customs official Freddy Esward.The accused private persons were regular travellers abroad.