Did I do the right thing ?

I recently started a new job. There was a guy today who started flirting with me (probably later 30’s?) and he gave me weird vibes so I kinda ignored him. UNTIL he came up to an 18 year old and I (21) while we were stocking shelves and started to tell us about how he’s having issues with his baby mom. Which then turned into him threatening to burn down her house or take his gun and shoot everyone who lives there. And not just once, but a few times. He also sounded really serious about it too. So I told a manager and he looked shocked. But then he asked if it was really true and it made me feel stupid for telling him