Milan prosecutors running checks on a successful plea for a presidential pardon by Silvio Berlusconi's former dental hygienist and ex People of Freedom (PdL) Lombardy regional councillor Nicole Minetti have found nothing untoward with the procedure so far, sources said on Thursday.

The Milanese investigators, who had given a positive opinion on the pardon on humanitarian grounds after Minetti said she had to care for a gravely ill child she adopted in Uruguay, are having a second look at the case and have involved Interpol after President Sergio Mattarella wrote to the justice ministry asking for clarification following press reports the plea was based on false declarations.

Minetti had a two year, 10 month sentence for pimping for sex parties at Berlusconi's home and a 13-month term for embezzlement as part of a reimbursement scandal that hit the Lombardy regional government pardoned in February.

The sources said checks so far run in Uruguay and Spain had not uncovered any reasons for the prosecutors to change their positive opinion of the pardon.

They added that the checks were not over yet.