“Amsterdam police during an investigation suspected that there was a plan afoot to spring a prisoner from jail” in the southern town of Roermond, the capital’s detective chief Olivier Dutilh said.

The prisoner’s accomplices “planned to hijack a helicopter… and use it to free the prisoner,” Dutilh told journalists at a press conference broadcast from Amsterdam.

“However, the plan was foiled,” the police chief said without giving further details.

Dutch media reported that a man — believed to have been one of the accomplices — was shot dead near Roermond, about 35 kilometres (21 miles) north of Maastricht, after a police chase.

Three other suspects were arrested.

“The men skipped a red traffic light and drove into oncoming traffic, followed by two police cars,” public broadcaster NOS said.

It said a suspected gun fight then broke out.

One of the suspects threw away an oblong suitcase which contained parts for an automatic rifle, police chief Dutilh added.

He said the prisoner was connected to “the Amsterdam criminal underworld.”

The NOS, quoting sources, said the prisoner is believed to be a member of the capital’s so-called “Mocro mafia” drug gangs of Moroccan and Antillean origin.

The gangs are known to fight among themselves for control of the city’s lucrative drug market, particularly cocaine, which has resulted in more than 20 assassinations of rivalling members in recent years. DM