Rahul Kumar, 18, son of Gaya MP Hari Manjhi, was taken into custody from a village near Bodh Gaya along with two friends on Sunday. Gaya Senior Superintendent of Police Garima Malik said he had been sent to judicial custody.
"Police conducted medical examination of Manjhi's son and it was confirmed that he consumed liquor," police officer Shuv Kumar Mahto said.
But Manjhi denied the charges and said his son was arrested to defame him ahead of the 2019 Lok Sabha polls.
The Bharatiya Janata Party and Nitish Kumar's Janata Dal-United are allies in Bihar. Complete prohibition was imposed in the state on April 5, 2016.