Cultivation of cannabis other than for specific industrial/horticulture purposes is illegal in India.
Officials confiscated ganja and poker chips sets from a flat at Chelavannur on Sunday, one person has been arrested.
Six cops suffered injuries during the mob attack.
Abhijith was arrested by police in connection with the case pertaining to the smuggling of 6.6 kg ganja worth more than Rs 7 lakh and 7 gm MDMA synthetic drugs worth Rs 50,000.
According to Manorama News report, all those arrested hail from Ernakulam district. They were arrested during a vehicle checking.
Civil Police Officer Tinu Joseph was injured and is recuperating at a hospital. A police jeep was also damaged in the attack.
Excise officers said the seized marijuana is worth Rs 100 crore in the international drug market.
All the four have been booked. The arrested are Vineeth, 20, of Adimali; Adarsh, 18, of Kochumadath Ernakulam; Sabin Rahman of Islam Nagar, Adimali, 22; and their 17-year-old accomplice.
It is suspected that a clash between rival gangs or between the members of the same group had led to the murder.
The four had purchased the ganja and the oil from Andhra Pradesh and were bringing them in the trucks under the guise of transporting chicken.