When that unsureness -to suspecting the person- don't send and if you had cut the transaction off, -better safe, than gnashing of teeth- this should be before any holistic examination on the suspect,
It was reported already 5days ago. This is a good reporting site for bitcoin scammers.
They do not use only that address, a new victim can get a clean and unspotted Bitcoin address, and will get a good tick if examined by this.
On social media someone complained to me how this springing up Ponzi scheme using ethereum scammed her, telling her it's there giveaway period and she has to send some ethereum to get her reward.
Give a bad tick to
+ Giveaways
+ Registering to -scam/ponzi-
+ Unknown unfriendly friend -he/she/them telling you to help him collect some btc in pretence-
+ Doubt stinking things -even from standard/real source-