MUMBAI: Parents of college students might want to double check what they are up to on WhatsApp. The Anti-Narcotics Cell (ANC) of Mumbai police on Monday arrested a man who supplied marijuana to students for orders placed over the app.Police penetrated one group on the app and zeroed in on Sunil Das, 29, who was nabbed at Vile Parle (East) with a 9 kg stash of marijuana worth Rs 1.8 lakh. Das lives in a flat on Juhu Tara Road.Das's use of WhatsApp is a departure from the usual modus operandi where peddlers wait in isolated stretches and buyers approach them. "Smoking weed for fun is a trend among college-goers. We found that college-goers are willing to pay five times more than the normal cost of marijuana," said the officer.Das has admitted to supplying marijuana to at least 150 students - mostly from colleges in the western suburbs - and his phone records revealed numbers of many. "We will summon the parents of every student Das was in touch with. Parents must know what their children are up to online. We haven't arrested any student as they weren't found in possession of the drugs," said an officer.