Puzzle 7: Full House
When a GP officer investigated a domestic despute he had the misfortune of finding the caller dead.
5 people left inside of the house are all suspects.
Everyone in the house had an allibi involving the other, but one of them is false.

Person A says Person was outside the house doing yard work.
Person B says Person C and A were in the basement
Person C says he and A were in the basement and saw Person D going upstairs
Person D says he and E went upstairs to check dinner
Person E says they were cooking dinner while A and D were doing chores

D is the culprit.  He has 3 seperate allibis putting him in to many places at once.  As the killer he was probably paranoid and went too far to garauntee his safety.