SPOILER question
If Tony didn't actually commit the murders, who did? Stasio's wife Selina?
shareTony DID commit the murders.
He planted the thumb in Angeline's paint box when he took the key from her wrist after sleeping with her the second time and she caught him red-handed and got angry with him. This was just before he was arrested.
He planned it together with Selina, Stasio's wife, to frame Angeline, get her put in jail so that Selina would get all the inheritance and share it with Tony. The ending is quite clear about this when it's just Tony and Selina in America discussing Angeline's fate.
Thanks for the help. But apparently Angeline did not know who killed them, did she? Thats why she had him whisper it to her.
shareAngeline was never 100% sure it was Tony as she didn't actually see what he was doing that night in Stasio's paint studio (when he was planting the thumb). She accuses him several times however, at the end of the film when Tony visits her in jail. Because he continues to deny it, and because she believes it so strongly to be him, she begs him to just tell her the truth otherwise she'll go crazy in jail thinking about it never quite knowing for absolute certain it was him. There was no real reason for him to whisper it to her other than for dramatic effect and to keep the audience in suspense just a little bit longer. But one can also hypothesise that even if Angeline was wired, by Tony whispering his guilt to her, the confession wouldn't have been picked up by a microphone.
In conclusion, Angeline always suspected Tony, and was convinced after she saw him doing the double movement with the lighter, which she testified to in court, but could never be 100% sure only because he kept denying it. She needed to hear him admit it. That's why she begged him to whisper it to her at the end.
Tony took a very big risk though. What if she had found the thumb and gotten rid of it, realizing it was a plant...
It was the only piece of evidence keeping him from being executed.
I am not a complete idiot. Some parts are missing.
Talking of risk, the biggest plot hole is that if his cop buddy was 5% more stunned after crashing his motor into the milk float, he would have been hung. A terrible scheme and a dreadful movie. Laura San G tried to keep the 'sexy, dirty and sultry' marketability going, and Neeson wanted to plump out his portfolio as he got ready for Schindler.