Police in Colombia have arrested six men in connection with a scheme to smuggle large quantities of marijuana and cocaine in passenger buses.
The arrests come days after police searching a bus which crashed in neighbouring Ecuador found it to be packed with hundreds of kilos of drugs.
The driver of the bus is being questioned by police.
Originally the number of people who died in the crash had been put at 24 but later reports said 23.
Officers searching the wreck of the bus for clues as to why it crashed did not at first find the stash of marijuana and cocaine.
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It was only after sniffer dogs alerted their handlers to the presence of drugs on the vehicle that officers found 80kg (175lb) of cocaine and more than 600kg of marijuana stashed in hidden compartments below the floor, in the seat cushions and in other parts of the vehicle’s metal frame.
The bus crashed in the early hours of the morning in Pichincha province.
It had left the south-western Colombian city of Cali on 5 August carrying, among others, a group of 40 Colombian holidaymakers from a working-class neighbourhood in Cali.
The passengers from Cali said they had been offered a free excursion to Peru via Ecuador. Some said they had been approached by a woman who accompanied them on the trip while others said they had been told the “freebie” was courtesy of a local politician.
Investigators suspect they were offered the trip free of cost to fill the bus with “tourists” to make it appear less conspicuous.
Ecuador’s chief counter-narcotics officer, Gen Carlos Alulema, said that the use of tour buses was “a new modus operandi used to smuggle drugs”.
Gen Alulema said the crashed bus was the fourth in which drugs had been found in recent months.
The prosecutor-general’s office in Colombia said that those arrested were part of a gang which had specialised in sending “narco-buses” from Colombia via Ecuador and Peru all the way to Chile.