Police have raided a pizzeria in western Germany which they alleged served customers a side of cocaine when they ordered item number 40 on the menu.

Authorities were tipped off about the scheme in March by food inspectors, and drug squad officers began watching the restaurant, criminal director Michael Graf von Moltke said on Monday.

When police went to detain the pizzeria manager at his apartment, the 36-year-old reportedly threw a bag of drugs out of the window, which "fell right into the arms of the police officers", Düsseldorf police said.

Police found 1.6kg (3.5lb) of cocaine, 400g (14.1oz) of cannabis and €268,000 (£223,120) in cash in the apartment.

The restaurant manager was released by police a few days later, and he reopened his restaurant and continued to sell the drug and pizza combination.

Investigators used the opportunity to explore the drug supply chain to the pizzeria, leading them to bust a drug ring in western Germany weeks later.

Around 150 officers raided two cannabis plantations - one in Mönchengladbach, to the west of Düsseldorf where 300 plants were found, and another in Solingen, to the east of the city, where 60 plants were found.

The homes and businesses of 12 suspects were also raided, resulting in the arrests of three people, including a 22-year-old suspected of being the head of the drug operation.

Police also found weapons, money and expensive watches during the raids.

The pizzeria manager was rearrested while trying to leave the country and remains in custody.

"The number 40 was one of the best-selling pizzas," Mr Moltke said.

Police have not released the name of others involved in the drug operation, or the price of the pizza and cocaine combination.