This was chopped from the original screenplay:


http://www.dailyscript.com/scripts/godfather2.html

KAY
I didn't even know he had a brother.
And where is he now?

MICHAEL
On a plane back to Sicily.

KAY
And that's all he had to do. Just
show his face.

MICHAEL
That's all. You see, in Sicily, in
the old days... there was only one
legitimate reason to kill a blood
relative... only one. IF he was a
traitor.

KAY
You would have killed his brother?

MICHAEL
Kay, you've got it wrong. That
kind of thing's all over, I promised
you. This was between the two
brothers. Years ago Frankie had a
young girlfriend; he called her his
co-wife. That was his joke, but he
meant it. He wouldn't divorce his
wife... because she was a great
cook. He said he girlfriend made a
spaghetti sauce once and it was so
terrible he knew he could never
marry her. He set her up in a
house in Jersey. She had to be
faithful... and she had to have kids.
And she did, two, a boy and a girl.
He had her checked out and watched
so she couldn't cheat... but the
girl couldn't stand that kind of
life. She begged him to let her go.
He did. He gave her money and made
her give up the kids. Then Frankie
took them to Italy, and had them
brought up by his brother Vincenzo.
Where he knew they'd by safe.

Kay begins to realize.

MICHAEL
When he saw his brother in the
hearing room, he knew what was at
stake.
(pause)
I don't think Vincenzo would have
done it. He loves the kids, too.
Omerta, Kay. Honor, silence. It
had nothing to do with me. It was
between those brothers.