A father and his 15-year-old son are seriously ill in hospital, after allegedly being shot at by an angry neighbour who objected to the illegal vape trade the two conducted from their balcony.

Three road workers who had been working near the flat at Rousseau street for the last three weeks saw dozens of youngsters standing in front of the apartment. The trade was conducted using a pulley. “The box came down, the €10 note went up. It was all go all the time,” one of the men told the AD.

Flavoured vapes have been banned in the Netherlands, boosting the trade in illegal sales. Neighbours said the practice had been going on at the flat for months and was conducted via Snapchat.

“Most buyers were around 12 or 13-years-old and came around 3 pm when school was finished,” one of the neighbours told the paper. Another said the crowds and litter were turning the situation into “a ticking time bomb. Something was going to happen,” another neighbour said.

Police have not confirmed an angry neighbour shot the two. “We are including it in our inquiry,” a police spokesman said. Shortly after the event police arrested a 55-year-old man and a 56-year-old man, both form Rotterdam, who are still in custody.

Housing cooperation Havensteder said it had no received any complaints about the alleged illegal vape trade.