What Happened?

What happened

It was Christmas day, and Mary, a young doctor, who had received an invitation the week, before to go to her friend, was getting ready in her room when she heard a suspect noise in the dining room. She was frightened, and so, she took the gun which was in her bedside table, and she became to go down the staris.
She was going down the stairs when she heard a new noise, so she stopped, and she heard someone fired a shot.
As softly as she could, she called the police, and she ran down the stairs.
When she arrived in the dining-room, a man was lying on the floor. Mary approched him and she can able to see he was died. There were so much blood.
The police came into the house, and a detective spoke with the woman about the man on the floor. He says to her that the man was Tom, a famous burglar, and he get a bullet to his stomach. So, he said to finish that the crime could be a revanche.
But this story is just in my imagination.