A former star panelist of BBC quiz show Eggheads could face questions from police about 12 dead bodies found in the canals of Amsterdam.
Born Joseph Connagh, De Mooi who lives in Monmouthshire, revealed in his autobiography that he may have killed a man while he lived on the streets two decades ago.
The 46-year-old said he punched a man who approached him with a knife and then threw him into a canal in Amsterdam in 1988.
He wrote in his autobiography: “He caught me on the wrong day and I just snapped.”
He added: “I fully suspect I killed him. I’ve no idea what happened to him.”
A spokesman for Netherlands Prosecution Service told The Sun: “The arrest warrant is based only on what he wrote in his book.
“We want to question him about the incident he described in the book.
“In 1988 the Amsterdam police has found around 12 bodies in the canals. One of them could be his victim if his story seems to be true.”
De Mooi could face extradition to the Netherlands if a European Arrest Warrant is approved.
A close friend of the star revealed De Mooi was first questioned over the matter six months ago – but refused to go back to Holland because “he didn’t trust the authorities there.”
He added: “CJ says he is completely innocent.”
CJ himself appeared to be upbeat about events, tweeting on Friday morning: “Good morning. However your week is going, please smile and have a wonderful day.”
A statement from the Metropolitan Police said: “A man was arrested at Heathrow Airport on Wednesday, 21 September on a European Arrest Warrant issued in the Netherlands in relation to an allegation of murder.
“Joseph Connagh, 46 (06/11/1969), self employed, of Monmouthshire appears in custody at Westminster Magistrates’ Court on Thursday, 22 September.”
The BBC reported that the warrant was issued in May by Dutch authorities requesting the opportunity for “further questioning”.
He appeared in front of District Judge Vanessa Baraitser on Thursday.
Sky News reported prosecutor Brian Gibbins said the arrest warrant was issued by a Dutch prosecutor over an allegation “relating to matters of manslaughter, murder, assault and assault by battery”.
He said that the warrant related to an incident said to have taken place in 1988.
He said that in De Mooi’s autobiography, “it said that the defendant claimed that whilst living in Amsterdam in 1988 he may have killed a drug addict who was attempting to mug him by punching him and throwing him into a canal in Amsterdam.”
“It is understood that person had a knife with him, it was said that the defendant punched his assailant square in the face, disarmed him and threw him in the canal.
He added: “On the face of the warrant he is wanted for further questions.”
The BBC reported that De Mooi, dressed in a green T-shirt and hooded top, spoke to confirm his name, age and address.
He was granted bail on the conditions that he does not travel overseas, sleeps at his home address every night and keeps a charged mobile phone with him at all times.
He was ordered to attend a further hearing on 28 November.
De Mooi became a panellist on the BBC Two show, which features five quiz champions competing as a team against different challengers, in 2003 after winning a series of game shows.
He adopted the name De Mooi when modelling, and he translates it as Dutch for “handsome”.