He took out the slim wooden stick out of his pocket. Panic flashed in her dark eyes. She prayed he would not, but then again. She heard him mutter the spell, "Avada Kedavra." All she saw was the green light. Then oblivion.
He saw her slender figure sway like a dead leaf and fall to the floor. Her face was frozen in eternal fear. He shook his head. Killing her was difficult. He did not want to, but he had to. He had to protect this secret at all cost.
He looks around and cleans the mess and his fingerprints with one swoosh of his wand. Then he proceeds to destroy anything remotely magical she had on her person. He fails to find her wand, though. Never mind, the Muggles won't understand even if they do manage to find it. Next he takes out his gun from his pocket and aims it at her. He shoots twice. First in her chest, second in her face. His shoulders sag in relief when he sees the blood seep out a little. At least the Muggles might think he killed her someplace else.
He frowns as he leaves that still-in-construction penthouse apartment where he had asked her to meet. He hopes her soul rests in peace. But she was such a menace anyway, he wonders if she ever will.
He knows the Muggles will find her. But they will never figure this one out. He allows himself some humour. Stupid Muggles, he thinks.
Five hours later, a man enters the new up and coming Park Court deluxe apartments. He whistles softly to himself as he lets himself in apartment number 302. He remembers having left his work folder there.
The body lies there. He sees it. Folder forgotten, he runs out and heaves his meager breakfast out. Her face, he shudders. The mobile gets taken out of his pants with shaky fingers and heavy breathes.
"101? There's a girl. She's dead."