Killer mummy on loose!

"Yes. Let me start from a few hours ago. At around 8 pm Dr. Watson returned home from his office. And at about 11pm he was murdered in his own house. Meanwhile, the main suspect, Ricky Warner, was seen escaping from the crime scene by Dr. Watson's wife Mrs. Serena Watson. After we searched Ricky's house we found him drunk in alcohol while dressed in bloodied clothes. We have already sent the sample to the lab. We'll know whose blood it is by morning."

Inspector Jolly described briefly. 

"Wait a second, I don't quite get it Inspector Jolly. The deceased was murdered in his own house. The suspect was seen escaping from the crime scene and later he was also caught red handed. If nothing goes wrong, the blood should also belong to the deceased Dr. Watson. This is clearly a closed and shut case . Where did the mummy come in from in this situation? "

Lisa asked with a confused look on her face.