The renowned reporter died on Thursday, nine days after being shot in the head in the centre of Amsterdam in a killing that shocked the country.
De Vries was renowned as a fearless campaigner who was a confidant of Nabil B, a key witness in the Marengo trial against Taghi.
Taghi is currently in custody and on trial with 16 of his associates, who face accusations relating to six gangland murders in the Netherlands as well as drugs trafficking charges.
The Dutch-Moroccan organised-crime boss is alleged to have formed a European 'super-mafia' with Daniel Kinahan as well as senior criminals from Bosnia, Italy and Chile.
In 2019, Taghi made a public statement denying reports he had threatened to have Mr de Vries killed.
Mr de Vries has been advising and acting as a confidant for a witness for Nabil B in the case against Taghi and his alleged associates.
B's defense attorney, Derk Wiersum, and B’s brother were also assassinated after Public Prosecutors announced a suspect had turned into a key witness in the Marengo process.
However, Van der Burg said authorities are also “also investigating other directions”.
“We understand very well that the link to Taghi was quickly established. But as likely as it may seem, we want to keep the investigation broad.”
Two suspects, 35-year-old Kamil E. from Maurik and 21-year-old Delano G from Rotterdam were arrested in connection with the murder.
It is believed the younger of the two was the one who pulled the trigger. According to De Telegraaf, G was linked to a group associated to Taghi. G's cousin Jaouad 'Joey' W used to head one of Taghi's "murder gangs".
Van der Burg urged for a tougher approach against organised crime in the Netherlands which includes offering adolescents more opportunities so they are not tempted to turn to crime.
“Structure in the neighbourhoods, education and sufficient job opportunities. You have to take every step to prevent the youth from thinking that they should turn to crime at all," Van der Burg said.
Investigations by the American Drug Enforcement Agency (DEA) established that Taghi was a prominent guest at Daniel Kinahan's wedding in Dubai in July 2017 while the Dutch criminal was on the run from police in his own country.
In February, it emerged that Kinahan was almost arrested by Dubai police in June 2019 in a hotel lobby when the Irish gangster went along to meet lawyers representing the fugitive mobster.