* 3 current managers, 3 former managers found guilty
* Accident on Autostrade-run motorway killed 40 people
* Autostrade says it will appeal guilty verdicts
* Company also under investigation for Genoa bridge collapse (Adds Deputy Prime Minister's comment)
By Francesca Landini and Stefano Bernabei
MILAN/ROME, Jan 11 (Reuters) - Three managers at Autostrade per l'Italia, and three former managers, were found guilty of manslaughter on Friday over the deaths of 40 people in a 2013 accident on one of the company's motorways, while CEO Giovanni Castellucci was acquitted.
The guilty verdicts by an Italian judge could open the door to potential damages suits against Autostrade, which is also under investigation after a bridge it operated collapsed in the Italian city of Genoa last August, killing 43 people.
The acquittal of Castellucci rekindled criticism against Autostrade, the motorways arm of Benetton-controlled infrastructure group Atlantia, from the Italian government. Deputy Prime Minister Luigi Di Maio, in a post on his Facebook page, called the verdict on Castellucci, who is also CEO of Atlantia, "incomprehensible" and reiterated that the government wants to withdraw Autostrade's motorway concessions in Italy.
The verdicts on Friday related to a case brought by state prosecutors after a coach travelling on a motorway linking Naples to Bari in southern Italy in July 2013 fell off a viaduct near the town of Avellino.
Autostrade, and the managers involved, were accused of poor maintenance of motorway barriers.
Autostrade's lawyer, Giorgio Perrone, said the company would appeal against the conviction of the six managers, who were given jail sentences of between five and six years.
The judge also sentenced the owner of the coach to 12 years in jail after investigators found the vehicle to be in poor condition.
Prosecutors had sought 10-year jail sentences for Castellucci and 11 other current and former managers at the company.
All 12 pleaded not guilty to the charges against them. Five were acquitted along with Castellucci. Three of those found guilty no longer work for Autostrade.
In a statement, Autostrade said it felt for the victims' relatives, adding it regretted the sentences handed out by the court to some of its managers.
"We are confident we can overturn the verdict for these six people who - in my opinion - were unfairly condemned," the company's lawyer Perrone told journalists attending the hearing.
Castellucci has already said he will step down as CEO of Autostrade after a 13-year tenure.
The 59-year old is also under investigation - together with other company executives, Autostrade and officials at Italy's transport ministry - for multiple manslaughter after the Genoa bridge collapse.
Autostrade has denied any wrongdoing in the Genoa disaster.
After the bridge collapse, the Italian government blamed Autostrade for poor maintenance of the viaduct and threatened to revoke the group's concessions.
The company, which runs 3,000 km of toll roads across Italy, generates more than 60 percent of Atlantia's core earnings. (Additional reporting by Amalia De Simone in Avellino; Editing by Susan Fenton)
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