BHOJPUR: Police arrested a youth in possession of 81.5 kilogram of marijuana from Mahendranagar-9 of Sunsari district on Thursday. The Eastern Regional Police Office, Biratnagar, identified the detainee as Siken Mukhiya. Acting on a tip-off, police said, they raided Shibu Mukhiya's house near the Saptakoshi dam at Mahendranagar-9 and seized the contraband packed in four sacks. Shibu is at large, police said.