Tuesday's operation saw two arrested for 'aggravated money laundering' and unveiled some of the valuable assets accrued from Maniero's mafia activities, including villas, luxury cars and bank accounts.
Among the treasures were a racehorse, eight Mercedes cars, a Bentley, two Porsches, two BMWs and three luxury villas.
The 62-year-old Maniero led the powerful Venetian Mala del Brenta mafia group - notorious for drug dealing, robberies, weapons trafficking and kidnappings - until the mid-1990s.
He was twice detained and twice escaped before entering into a fraught collaboration with Italian justice authorities which led to the dismantling of his organized crime network.
In 1997 Maniero was jailed for 19 years for nine murders committed between 1982 and 1994. He was released from prison in 2010 and given a new identity.
Italian media tracked Maniero down in 2015, managing a water purification company.
However, he repeatedly refused to reveal the location of his 'treasures', acquired from his time leading the clan - before finally agreeing to collaborate in March last year.
At the start of last year the authorities reopened their inquiries in a bid to recover some of the valuable assets accrued from his mafia activities, estimated to be worth some €17 million.
Those inquiries turned up investments in prestigious real estate managed by Maniero family members.