The Old Haunted House

There was once a legend said that an old man and an old woman died in their house on a cold foggy Halloween night while sleeping in their bed. Before they lived in the house, the couple before them died in their bed too. People call the house the Haunted House of Dead.
A couple of years after that, four girls, Sacha, Sonya, Shelley, and Shawna, all the age of 13, decided to go trick or treating together. Shawna ran to the Haunted House and rang the doorbell. Sonya and the other girls finally arrived at the house and told her that no one was going to answer. Shawna didn't hear what happened and Shelley told her the whole story. Shawna didn't believe her. Sacha dared her to go in the house, to go upstairs, and to stick a knife through the middle of the bed.
Shawna went into the house all brave and cool. She walked upstairs to the bedroom, and she put the knife thorugh the middle of the bed. Somehow the knife caught the sleeve of her costume and she went in shock and died.
Two hours later the three girls didn't see Shawna, so they went home and told Sacha's parents, who called the police. The police went in the house and upstairs to the bedroom. They saw Shawna laying on the bed dead.
The police said when the knife went through the sleeve of her costume, she probably thought that the old lady or the old man grabbed her arm , and she went into shock and died.