The occupants were college students who likely didn't have renters insurance.
I'd like to take this opportunity to mention renters insurance. In a case like this, these 4 students are liable for the damage since they caused the fire by their choice of furniture placement. The owner's insurance company will sue them for damages. If they have renters insurance, they are covered up to the amount they are insured for. (In an area like this one, make sure the insurace will cover the expensive property values here.) Renter's insurace would also pay replacement value for their stuff. You can also add a personal liability policy that will protect you in case you are sued for damaging some property at someone else's house or a public place, or other types of personal lawsuits.
Most companies that insure your car will offer renters insurace too and you may get a discount on your auto insurance when you open a policy.
And no, I do not work for an insurance company!