But they think he must have stumbled upon the guys who did.

The first time, back in 1999, I just stumbled upon it.

How did we happen to stumble upon such a perfect moment?

Someone stumbling upon our conversation would believe we were talking about people.

Perhaps they would've come to mind had he not stumbled upon a couple of million in cash.

It's not hard to stumble upon free books these days.

By accident, he stumbled upon the two men and the girl.

I feel as if we had stumbled upon a black, hidden river, running under our very feet.

By accident my mother had stumbled upon her life's work.

He tried to imagine how the senator had stumbled upon the place.