SALEM – A Peabody man authorities said was involved in a gambling enterprise with the mafia is free on $15,000 cash bail after pleading innocent.Michael Petrillo, 56, of 6 Maryrose Way, Peabody, appeared Thursday in Salem Superior Court, pleading innocent to receiving stolen property, accessory after the fact, using a telephone for gambling purposes and conspiracy.Judge Timothy Q. Feeley agreed to set the cash bail, which Petrillo immediately posted, and continued the case to Jan. 31.Petrillo was arrested during the October sweep by Massachusetts State Police involving an ongoing investigation into criminal activity in which 31 people, including reputed capo Mark Rossetti, 50, of East Boston, were arrested.Assistant District Attorney Jack Dawley said the charges against Petrillo and another co-conspirator, Joseph Giallanella, stem from dates dating back to 2009.Police searched Petrillo’s home on June 17 and found a number of gaming slips at his home, Dawley said.Police then went to Giallanella’s North Andover home and seized safety deposit keys to two banks in Boston which contained $1.3 million, according to Dawley.Giallanella, 62, of 134 Candlestick Road, North Andover, also pleaded innocent to managing a gaming enterprise, using a telephone for gaming, conspiracy, accessory after the fact and usury charges.