Amateurish.
They were smart enough to find out where the dead dudes lived and burglarize the now presumed empty home, but stupid enough to take things that were going to lead the police right to them.
They could have shut down the computer and put it in a faraday bag, but the car is pretty much going to bring the police to your door. Maybe you could put it in a sheetmetal shed? Disconnect the satellite antenna?
People with the kind of money that the victims had generally have domestic help of one kind or another. A gardner, cleaning lady, handman, who sometimes bring their kids along to help. When they died the word about how much lucre was laying around the house must and where it was must have gotten out. I knew a physician who left a bank logoed bag with $5,000 in cash on a home office desk unattended, while the cleaning lady and her daughter were vaccuuming the house. "I've know her for years!" The daughter is eighteen, and even if she does not have a sense of entitlement, she has lots of friends who do.