16 people were arrested during a specialised police operation in Smolyan region, the Ministry of Interior said on June 6.
Most of those arrested are British citizens residing in the Smolyan village of Polkovnik Serafimovo, where a festival was held over the weekend.
They were arrested for drug possession, driving under the influence of drugs and alcohol.
Pre-trial proceedings have been opened.
Майката на загиналото момче край Мездра: Той не искаше да минава оттам, но явно някой друг реши съдбата им
"Писна ми да убиват нашите деца": Бдения в страната в памет на загиналите по пътищата