A man who was shot and killed in Buitenveldert in Amsterdam on Wednesday morning has been identified as Derk Wiersum, a lawyer that represented a key witness who had linked wanted fugitive Ridouan Taghi to multiple assassinations, the NL Times reports.

Dutch Prime Minister  Mark Rutte, MPs and lawyers have expressed shock at the murder, calling it an assault on the rule of law, the news report reads.

The police are still looking for the man responsible, described as a man between 16 and 20 years old.

Wiersum is not the first person connected to the witness to be assassinated. The witness' brother was killed a week after the public prosecutor had announced that it made a suspect turn key witness, NL Times states.