There was NO excuse whatsoever not to have used a rectal thermometer in which to give them an appx time of death. I see no reason why they didn't,as it's carried out at ALL murder scenes that the police are called out to,unless the body has lain for days.
Unless a temperature reading of the scene and body temperature are both taken very early upon finding the body then it is worthless.
Such can't be done off scene it needs to be done on scnee and the records have to be taken as soon as possible. The temperature will drop to the temperature of the room the body is in. The interval can vary which is why you would want to keep taking readings to see if you could get as close as possible to the interval the drop is occurring at.
Moreover natural body temperature fluctuates. Even though 98.6F is normal body temperature in reality the body temperature will fluctuate between 96.7 and 99. Rectal temp is actually higher than this, the average rectal temp is 99.1-99.35F BUT can fluctuate between 97.2 and 99.75.
So right off the bat this natural fluctuation creates a situation where we don't know what the original temperature was and thus the estimate can be thrown off by several hours.
Clothing and other variables make it hard to know precisely what the heat loss rate will be which is why we have to monitor it to try to figure out the exact rate in the situation at hand. Just using some generic rate will be imprecise and cause even a great margin of error. Worse yet loss of heat is not necessarily uniform. Even though we like to pretend heat loss will be 1.5 degrees F per hour sometimes a body will lose less sometimes more it will not be uniform hourly loss necessarily.
Using the 1.5 loss rate the margin of error will be several hours. The variation of the starting temp at death will cause more problems. You still need the temperature of the environment in the meantime which also can fluctuate.
Let's assume the deaths occurred at 2:30AM. They were exained 3:30PM and later.
Suppose their temperature at 3:30AM was 72 degrees. Suppose also they had been in the cold morgue for 2 hours but before that had been in a hot truck.
How are you supposed to figure anything out accurately? Initial body temp could have been anywhere from 97.2 and 99.75. Plugging in the 1.5F/hour loss rate we get 16.8-18.5 hours.
But being placed in a hot truck not only could have inhibited loss it could have caused the body to heat. Placing it in the cool morgue would cause more rapid cooling. It could be greatly distorted by this.
You need reliable readings of the environment where the bodies were found and the readings at those times to even have any hope of giving a range with an error rate of only 1.5-2 hours.