Dubai police on Monday arrested the alleged head of a cocaine-trafficking gang described as the most wanted man in the Netherlands, officials said.
Moroccan-born Ridouan Taghi, 41, who was wanted on international arrest warrants for murder and drug trafficking, was held at a house in the Gulf emirate.
Taghi hit the headlines in September when a Dutch lawyer for a state witness in a case against him was shot dead near his home in Amsterdam.
Dutch police chief Erik Akerboom said Taghi's arrest was of "great importance for the Netherlands" and followed cooperation between the two countries.
Dubai police said in a statement that Taghi "entered the country through Dubai's airport, using a passport and a visa with a fake identity."
It added that he lived in a residential area in Dubai "where he wasn't exercising any criminal activity", and where he had "assistants from various nationalities."
Dubai police said that the person "confessed to all crimes."
Dutch media said Taghi was accused of cocaine trafficking. The Netherlands and Dubai had no extradition treaty but authorities in both countries were working on transferring him, broadcaster NOS said.
Pressure mounted on Dutch authorities to act in September after lawyer Derk Wiersum, a father of two, was killed in Amsterdam.
Wiersum was the lawyer for a state witness named Nabil B. in a huge case against Taghi and another suspect wanted on similar charges, Said Razzouki.
The Netherlands has long been known for its tolerant attitude towards marijuana but a report commissioned by Amsterdam city council this year said it now had a major problem with drugs and the criminal underworld.
One of the main Dutch police unions said at the time that the lawyer's shooting was "confirmation that we live in a narco-state".