Dutch drug kingpin Ridouan Taghi received a life sentence on Tuesday over a series of murders committed by his gang that shocked the Netherlands.

Taghi, 46, is the alleged mastermind of the Amsterdam-based group called the "Mocro-maffia" that is thought to be one of the Netherlands' largest cocaine distributors.

Security around the trial has been extremely tight with judges and prosecutors asking not to be identified. At least three people directly connected to the mega six-year trial have been killed.

"We are sentencing all 17 suspects. Ridouan Taghi gets life in prison," said a judge at the Amsterdam District Court.

Taghi was the "undisputed leader" of what the judge called a "murder organisation."

"He decided who would be killed and he spared no-one," said the judge, whose face was not shown on a television feed.

Sixteen other suspects were handed sentences ranging between life and one year and nine months.

Taghi's sentence can be reviewed after 25 years, but it did not mean he was automatically eligible for parole, public prosecutors told AFP. Taghi was not present in the courtroom.

A lawyer for another suspect, named Said R., said his client would appeal a life sentence.

Once the Netherlands' most-wanted fugitive, Taghi was arrested in Dubai in 2019.

Despite being held at an ultra-secure prison, prosecutors say he continued pulling the strings, sending secret messages to henchmen on the outside.

- Ring of steel -

Heavily-armed police on Tuesday threw a ring of steel around the courthouse nicknamed "The Bunker", on the outskirts of Amsterdam.

Officers armed with automatic rifles and wearing face masks to protect their identities were guarding the court, while drones and a police helicopter circled overhead, AFP correspondents saw.

Taghi and 16 other accused did not face charges for the three murders that occurred during their trial.

They faced six other counts of murder and attempted murder -- including ordering some 13 hits -- carried out between 2015 and 2017 mainly against people suspected of becoming police informants.

On Tuesday, Taghi was convicted on five murder counts, including on a man called Hakim Changachi, who was gunned down in Utrecht in 2017 in what prosecutors say was a case of mistaken identity.

"Taghi was responsible for the mistake," said the judge.

Shortly afterwards police made a breakthrough in the case, when one of the suspected gang members named "Nabil B." handed himself over and agreed to become the prosecution's main witness.

A new wave of violence followed after Nabil B. turned state witness, leaving three people dead in scenes that shocked the nation.

Nabil B.'s brother was murdered in 2018, his lawyer Derk Wiersum was shot dead outside his house in 2019, and the prominent Dutch crime journalist Peter R. de Vries was killed in 2021.

De Vries acted as Nabil B.'s confidant at the time of his murder and had said before he was on Taghi's hit-list.

Taghi's gang was nicknamed the "Mocro-maffia" because its members are mainly of Moroccan and Antillean origin.

Taghi has denied all charges, and has said money spent on a "sham trial could rather have gone to employing more teachers and police and healthcare."

- 'Pitch black edge' -

None of the suspects made any statements during the trial, which was delayed by several dramatic developments.

Taghi's lawyer Inez Weski was arrested in April last year, with prosecutors accusing her of passing messages between her client and the outside world.

New lawyers were appointed for Taghi, but they too have since resigned.

The prosecution's case consisted of more than 800 pages with evidence not only from Nabil B., but also conversations from encrypted telephones called "Pretty Good Privacy" (PGP) phones, often favoured by criminal organisations.

"We would like to take a moment to remember the three people murdered during the hearings," the judge said on Tuesday.

"All of this has given this trial a pitch-black edge."

Dutch MPs hailed the conviction, with far-right politician Geert Wilders' -- whose PVV party won last year's elections -- saying on X, formerly Twitter, "it's a beautiful day for the Netherlands."