Why was Doug Hoo stationed outside the Westing house?

I believe that this question is asking about events that happen at the very beginning of chapter 4. It is Halloween, and Turtle Wexler is planning on spending the night in the Westing house. The second paragraph of this chapter tells readers that Doug Hoo is up on the top of the cliff where he had taken his "station" behind the maple tree. Doug Hoo is the chosen timekeeper for Turtle Wexler's time spent in the Westing house. Doug Hoo is the chosen timekeeper because he's a track star that can run faster than anybody else in the entire state. Turtle is absolutely planning to spend the entire night in the house because it will make her a lot of money. She's being paid two dollars per minute for being in the house. Unfortunately, her time is cut short, and she is only in there for twelve minutes. She runs out of the house screaming because she finds a dead body.

Turtle had seen the corpse in the Westing house, but it was not rotting and it was not sprawled on an Oriental rug. The dead man was tucked in a four-poster bed.