Bryan Kohberger allegedly entered a house with a knife and slaughtered 4 people when 6 people and a dog were in the 3-level home, so how could a first-time killer pull that off?

TMZ Studios has a new series, "Strange & Suspicious," which begins airing Monday on a dozen FOX stations, where we explore strange, unexplained and downright weird stories, and the Idaho murder case raises lots of questions.

According to prosecutors, Kohberger first killed Kaylee Goncalves and Madison Mogen on the third floor of the house, then went downstairs and killed Xana Kernodle and Ethan Chapin. He then allegedly encountered one of the 2 survivors in the house but didn't harm her, and then he left.

There are so many questions ... he was getting an advanced degree in criminal justice, so how did he gamble no one would scream and the others would overtake him? How was he protecting himself from a dog that could attack him? If he was after one of the women, why didn't he wait until she left the house? Lots of questions.

"Strange & Suspicious" -- from UFOs to true crime to bizarre phenomena ... click here to see when and where the show airs.