(Bloomberg) -- Interpol is warning authorities across the world of a new trick drug dealers are using to supply clients during the coronavirus lockdown -- posing as food-delivery drivers.

Spanish police arrested seven people who dressed as drivers to sell cocaine and marijuana in Alicante and Valencia in early April, Interpol said in a statement Thursday. Some drugs had been hidden in a false bottom of delivery backpacks.

Interpol said it issued a notice detailing this new modus operandi to warn its 194 member countries and help authorities address shifting crime patterns. The crime agency said a variety of food-delivery services could be affected.

Worldwide lockdowns to slow the Covid-19’s spread have forced people to stay at home and order takeout. Germany’s Delivery Hero SE said Tuesday that orders in the first quarter nearly doubled from a year earlier. Just Eat Takeaway saw a 50% jump in first-quarter orders.

In many of the cases, couriers wore backpacks and insulated bags emblazoned with the distinctive names of those services.

Interpol said some delivery riders may be complicit in drug transportation. The global policing body said examples had been brought to its attention where legitimate drivers knowingly delivered drugs on behalf of criminal organizations for financial gain.

But real drivers may have been used as unwitting drug mules, Interpol said.

In one Malaysian case, a man in Kuala Lumpur contacted police and asked for his food package to be inspected after he became suspicious. He had been supposed to deliver a single order of Indian flatbread, but the parcel weighed about 11 kilograms (24 pounds).

©2020 Bloomberg L.P.