When you interrupt a crime in progress and take action to stop it, you are not a vigilante. A vigilante is one who takes action AFTER a crime has been committed, but ended.
There is a difference, one major difference - timing.
PS: If it were my daughter of granddaughter who was being attacked, I wouldn’t be thinking about “vigilantism”. I’d be thinking how can I kill this bastard ASAP.
Exactly. Which would you rather tell your little girl?
"I know that bad man hurt you honey, but he will never hurt anyone again."
Or...
"Maybe he won't come up for parole for at least twenty years."
One way the child gets closure, and can start getting on with picking up the pieces and living, the other way, every shadow will hold a boogeyman.