You had your boyfriend's "friend" over (she was a female) and they both flirted and chatted, leaving you left out a bit.

You all 3 went outside to breathe fresh air until you all heard something.

There was a guy with a weapon, and a mask. He grabbed the girl, but you tried to grab her away but instead the guy snatched you and held the weapon to your throat

The girl and your boyfriend quickly ran away together, leaving you alone.

The killer stood a bit, the weapon still on your throat, until he took off his mask. His dark brown hair is sweaty and his dark green eyes looking the way they went

"Damn.." he muttered