Ha assistito all'incidente.

[morbrorper]

English Translation

He witnessed the accident.

I think this is “witnessed” as in “was present at”.

[anon94972132]

I am not sure about this one.

I tend to understand it as “he helped at the site of the accident” e.g. helping the victims to climb out of the wreck.

[Floria7]

Agree with @morbrorper here. Assistito also means to attend.

Un falso amico eh;-)