In Darlie's case, we see mixed motives as well. Anyone looking at this crime should draw a big, imaginary circle around the boys being stabbed because that is the true crime here and that indicates a personal motive. The whole business about the "phantom" or "intruder" is an attempt to introduce an economic motive into the crime ("somebody came in here and tried to steal our things!"). This is simply another case of someone trying to claim an interrupted burglary and it is fairly common even though the economic motive parts are staged. That is, the overturned vacuum, the smashed wine glass, and the sock in the alley are all there to try and make people believe this crime had an economic motive when it is fairly clear that the real crime, the stabbing of the boys, had a personal motive.
In this case, the importance of the intruder is obvious: to show that someone else committed the crime or that there is at least reasonable doubt about who do it. However, the more important reason for suggesting an intruder is to introduce a second motive for the crime, the all-too-common "interrupted burglary," an economic motive. In other words, if someone had entered the house just after Darlie had finished stabbing the children, she would not be able to explain away the stab wounds on the children, a personal motive. The staging suggests an economic motive, and many of those people who believe she is innocent do so because they can't separate the genuine motive, the stabbing, from the staged motive, the economic one.
Too, Darlie and her family have tried very hard to sell the staged motive, the economic one. On the 911 call, as we know, Darlie suggests that an intruder, not she, committed the crime because she says that if she hadn't touched the knife, maybe police could have gotten some prints off of it (translation--it was somebody else who committed the crime, not Darlie). Later in the 911 call, she says that she and Darin "have to find the person who did this" once again suggesting that an intruder did it. Finally, she also adds in the call the question of "who could have done this" which is once again a sorry attempt to suggest that someone else, not Darlie, committed this crime. There is, of course, the other staging I have mentioned and my belief is that it was Darlie who smashed the wine glass, overturned the vacuum, and cut the screen while it was Darin (by process of elimination, the only person who would have had the time to do it), who placed the sock in the alley to suggest that an intruder had broken in their house. The 911 call is what I like to refer to as the first sorry attempt to create the intruder and the sock in the alley, etc, is the second sorry attempt to create the intruder. The third sorry attempt to create the intruder is when Bob Kee, Darlie's stepfather, files an affidavit two years after the trial that says Darin talked to him about a fake burglary scheme a few nights before the murder. I believe this is simply a clever trap. A reporter approached Darin and asked about whether Darin talked about a faked burglary scheme with his stepfather-in-law. Darin initially denied it, but the reporter went and got the affidavit that Bob Kee had filed and confronted Darin about it. Although Darin has been described as "headstrong," he meekly caves in and says that yes, he had talked about a faked burglary scheme with Bob Kee, and someone may have overheard it and acted upon it. In my opinion, Darin meekly caved in to try and introduce the intruder in this case, an economic motive. He also added that he told someone years earlier that he wouldnt mind if his Jaguar got stolen, and it was; in my opinion, he is simply trying to bolster his street credentials as someone who would do this sort of thing all in an attempt to create the thought that yes, it is possible that there was an intruder in this case. Notice how Darin is utterly defiant when it is pointed out to him that he could not get the loan he was seeking shortly before the murders and when people bring up his failures on the lie detector test, yet he meekly caves in when people suggest he is a little bit shady and someone could have broken in his house at his suggestion to further a burglary scheme. The fourth sad attempt to create the economic motive is the defense effort to try and get items DNA tested to show that the intruder was involved. I believe the defense should do that, but I am not holding my breath that we are going to find the intruder that her family is desperately trying to create because the true motive, in my opinion, was the personal one of stabbing the two children in a jealous rage