The family of the former deputy prime minister Andre Cools, shot dead in 1991, called on prosecutors to lift the immunity of Mr Wathelet, who was Belgian minister of justice from 1988 to 1995.
The family accused Mr Wathelet, a member of the Christian Socialist Party (PSC), and formerly a prominent politician in the Walloon region, of impeding the course of justice during the inquiries which followed Cools's killing. The family are furious that several suspects first identified in relation to the killing in 1992 were arrested only at the weekend.
No evidence was produced to justify the allegations against Mr Wathelet, which come amid widespread public suspicion against all Belgian politicians.
As the scandal continued to produce revelations, it emerged separately yesterday that new evidence had been given to the authorities suggesting that the Cools killing may have been carried out by Sicilian Mafia hitmen, as long suspected.
Belgian television reported that the prosecutors now have the names of the two killers, who are said to be Tunisian in origin, with Sicilian ties. The identities of the men, who have not been arrested, came to light during a raid by tax authorities on a Belgian house.
Le Soir reported that the authorities now have confirmation that the killers were recruited in Canicatti, in Sicily. According to the newspaper, the investigators had evidence to this effect, based on telephone tappings, dating back to 1991.
However, the Belgian authorities have yet to produce any explanation of the motive for the murder of Cools, who was prominent socialist politician, thought to have been shot on the order of political rivals.
The authorities have also failed to confirm clear links between the Cools inquiry and the inquiry into the child sex ring of Marc Dutroux. Speculation of a link followed the revelation that some of the same individuals had been questioned in both inquiries.
The accusations by the Cools family against Mr Wathelet are not the first to be made against the Luxembourg judge since the Belgian crisis broke.
Following the discovery of child murder and sex abuse allegedly perpetrated by Dutroux and his accomplices, Mr Wathelet was accused by the families of the dead girls of letting Dutroux walk free during his period as justice minister. It was Mr Wathelet who agreed to Dutroux's release when he had completed three years of a 13-year sentence for child rape.
The accusations made yesterday against Mr Wathelet are separate, and relate to the way he oversaw the inquiries in the Cools murder. However, given the connections already made between the two cases, Mr Wathelet's name is certain to come under the spotlight.
There was no reason to believe the prosecutors will order the lifting of Mr Wathelet's immunity in the immediate future. All Belgian ministers and former ministers enjoy immunity from prosecution in relation to their political activities.
Jean-Michel Nihoul, previously charged only with criminal association in the child-abuse scandal, had the charge of kidnapping added yesterday.
Public Prosecutor Michel Bourlet said Nihoul was now officially linked to the abduction on 9 August of 14-year-old Laetitia Delhez .Reuse content