How do you know ?

"Jack, watch what you say. Observe who you are speaking of." The guy immediately withdrew after Stefan gave him the warning, but Gabriel's disposition soured upon seeing Eveline with Alex.

His words were bluntly ignored by Eveline and that irked Gabriel a lot.

"Come on, Gabby, ignore them, and let us just focus on the practice." Stefan tried to divert Gabriel's attention, but all he got in return was a chilly stare. 

Gabriel let go of the basketball in his hand and walked towards Stefan dangerously.

"Why did not you tell me Eveline knows hacking?" he asked, leading him to a corner of the ground. "Oh, in fact, you are the one who taught her." Gabriel had humor in his words, however, his eyes were drilling holes into his soul.

"Gab, I-I can explain," stumbled Stefan, realizing that he had been wrong to withhold such a significant aspect of Eveline from him.