Godfather Pino Scaduto began blaming his earlier arrest and conviction on his daughter's burgeoning relationship with a senior Italian policeman.
Investigators scouring his prison correspondence discovered chilling references to a specific "gift" he wanted to give to his daughter.
Detectives say Scaduto, who was released from prison in April, then told his son to kill her, with the words: "Your sister has become an informer".
But Scaduto junior, who is already facing a separate murder charge, was reluctant to obey.
"I don't want to do it," he said, in a conversation intercepted by police. "If you want it done, do it yourself. Why should I deal with the problem? I'm 30."
Scaduto senior, who rules over the Bagheria syndicate near the Sicilian capital of Palermo, then tried to hand the job to another person, who turned it down on the basis it was a family dispute.
"Today, we have arrested a crime boss who wanted to kill his own daughter because she was in a relationship with an Italian police major," Italy's foreign affairs minister Angelino Alfano said Monday, according to media reports.
"The mafia define themselves as men of honour. But where is the honour in ordering the killing of your child?" the minister said.
Scaduto was arrested alongside fifteen other members of the Bagheria clan.
They are all accused of mafia association and extortion targeting local entrepreneurs in the construction and mineral water sectors.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)