If not robbery then what is the motive? If it was a quick in and out crime, it seems like it was planned to kill both of the people in the home. The father had just died of cancer, could someone have wanted the remaining daughter to get an inheritance? If some one wanted to kill or beat the mom or the daughter alone, why wait until they are home together.
It still seems like the daughter was the target and they killed mom first to get her out of the way. Why would someone want to kill her? She was moving away to school, did they have to act fast before she left? Was some girl jealous and she got friends to help her? The murders occurred right after the mom put pictures of the prom dress on Facebook (which was open for anyone to see, not private). Did the prom dress pictures trigger some real feelings of hate? Was there someone who was angry that the daughter was going to the prom with someone they wanted to be with? I hope all these angles have been looked at by LE.
As LE has provided tiny information, we have to work with the little they say and what can be deduced from the few references of the family. But we would need to know more information before discarding hypothesis, for example, that there is only one murderer.
Consider the issue of weapons. We know, but not by the police, that at least three different types of weapons were used. But we do not know if the killers brought all weapons or took any from inside the house. We do not know if they took all with them or left one behind. A gun, a knife or similar, a blunt object, perhaps an iron bar or bat.
Or the places where the bodies and signs of struggle or blood stains were found.
Or what happened to pets: two dogs and two cats.
There is something that puzzles me. At first detectives refused to say they were faced with a double homicide, ensuring that it could also be a murder-suicide. The only way that a murder-suicide option could be taken into account in a rational manner is that a gun was found near the body of Kathy. Or detectives were deceiving. An absurd attempt to hide information, as they did from the very beginning, and no one has yet explained why. I am inclined to believe the latter possibility. Indeed, it would be interesting to know if Kathy had a gun at home.
A robbery? It would be rather strange, for several reasons:
Kathy did not have much money, she was a widow with a job as a teacher, with two student daughters and many expenses. The house is very old and does not look wealth.
The house was empty most of the day, so any time would have been good for a robbery, except when the victims were inside. Kathy's car indicated that someone was in the house.
The time. At 20:00 it was still daylight and there was enough light for anyone to see the car or its occupants to enter and left the house.
I'm sure the surviving daughter was the first suspect and the most widely investigated, but it seems that detectives found nothing. Apparently there was a life insurance policy of $ 50,000, but does not seem a very large amount, nor that she needed money or carry a doubtful style of life.
Samantha was leaving to the Gatton Academy, and she and her mother were interviewed by a newspaper three weeks before the murders (
LINK). Envy which turns into hatred? It is possible, but these things do not usually start suddenly with a murder, and offenders are often not able to hide his feelings. It is usual to start with verbal attacks, insults, attacks on objects or pets of the victims, small aggressions ... That is why I was concerned about the damage to the door.
But if someone developed envy and hatred to actually kill, and has been able to hide his feelings throughout the process, this is the most dangerous kind of murderer, someone who will kill again for sure. I hope that it is not the case.
Samantha had just the first date with her first "boyfriend", who was to accompany her to the graduation, but there seems to be nothing on that side. Surely the police investigated it.
Was Samantha the main target? I have doubts. If the goal was to get rid of Kahty to develope hate on Samantha, why shoot and make noise? Why not kill Kathy with the same weapons used with his daughter? If the gun had had a good silencer, it will clarify this point, but would provoke new puzzling questions
If some one wanted to kill or beat the mom or the daughter alone, why wait until they are home together.
It's a very good question, but probably there would be no many times when she was alone in the house. If the target was Samantha, it might be difficult to find her alone.
The family says the blows to the head to kill Samantha indicate anger and that perhaps it was personal, but I'm not so sure. From some comments, I think that the blows were to the head, but not in the face, or at least not primarily in the face. Perhaps they interpret as anger what was no more than the adrenaline released in an attempt to kill a person. But without autopsy data, we can not say more than this.
A random killing? The lack of motives could point in that direction, but who and why? In addition, we should clarify what we mean by random. Two or three guys in an Impala pass through a road and suddenly say, hey, let's kill whoever live in that house. It does not seem very credible, especially in places where many people have a gun at home and they did not know if there were one or ten people inside. Were the victims monitored before? But then, to what extent can we speak of random?
One last thing. In the case of Crystal Rogers, it has been presented almost all the information, including hours of interrogatories in video. They have not even told us how Kahty and Samantha died.