see

see + noun/pronoun + -ing form
I saw him talking to someone.
I saw him talks to someone. (wrong)
I saw him talked to someone. (wrong)
I saw him to talk to someone. (wrong)

When see is used with an -ing form, it emphasizes the action in progress.

see + noun/pronoun + base form
I saw her leave a few minutes ago.
I saw her leaves a few minutes ago. (wrong)
I saw her left a few minutes ago. (wrong)
I saw her to leave a few minutes ago. (wrong)

When see is used with a base form, it emphasizes the action seen as a whole (from start to finish) or as completed.