Forensics PMI

Case 1

Police Report: The body of a female deer was found behind a fence along a busy two-lane road on the edge of the city limits of Charlotte. Animal Control was called and reported no apparent wounds on the body. It was not hunting season.

Weather Report: Daytime temperatures have been fairly consistent for the past three weeks, ranging from 70 to 74º F.

There were 2 house fly larvae that measure 29 & 20 mm, 2 blow fly larvae at 29 & 25 mm, 1 flesh fly larvae that was 29 mm a skipper fly larvae that was 9 mm and 1 flesh fly pupae that measured 39 mm.

Based on the sizes of the fly larvae, what is the PMI of the deer? Use the table to help you determine the PMI.

• 18 + days

• 10 - 11 days

• 5-6 days

Case 1:

Police Report: The body of a female deer was found behind a fence along a busy two-lane road on the edge of the city limits of Charlotte. Animal Control was called and reported no apparent wounds on the body. It was not hunting season.

Weather Report: Daytime temperatures have been fairly consistent for the past three weeks, ranging from 70 to 74º F.

There were 2 house fly larvae that measure 29 & 20 mm, 2 blow fly larvae at 29 & 25 mm, 1 flesh fly larvae that was 29 mm a skipper fly larvae that was 9 mm and 1 flesh fly pupae that measured 39 mm.

Why are there larvae of different ages for the same type of fly found on the body of the deer?

• They measured wrong

• The different flies come to the deer at different times.

• Adult flies of the same species came to the deer at different times

Case 1:

Police Report: The body of a female deer was found behind a fence along a busy two-lane road on the edge of the city limits of Charlotte. Animal Control was called and reported no apparent wounds on the body. It was not hunting season.

Weather Report: Daytime temperatures have been fairly consistent for the past three weeks, ranging from 70 to 74º F.

Other than the temperature, what other abiotic factors (nonliving things) do you need to know about the weather for the past couple of days in order to be confident about the time of death? Check all that apply

• Humidity

• Cloud Cover

• Precipitation

• Amount of traffic o road

Tags

NGSS.MS-ESS2-5

Case 1:

Police Report: The body of a female deer was found behind a fence along a busy two-lane road on the edge of the city limits of Charlotte. Animal Control was called and reported no apparent wounds on the body. It was not hunting season.

Weather Report: Daytime temperatures have been fairly consistent for the past three weeks, ranging from 70 to 74º F.

Why do you not need to change the PMI based on the temperature?

• The temperature of the environment is hotter than the temperature in the table.

• The temperature range of the environment is within the range of the temperature in the table.

• It is temperature of the environment is colder than the temperature in the table.

Case 2 :

Police Report: The body of a large pit bull terrier was found inside a walk-in basement at a home in Cary. Maggots were found concentrated in the head and region behind the shoulder. The windows were closed, although the open curtains allowed sunlight to enter, and the air conditioner was set at 72º F.

Weather Report: Daytime temperatures have been variable over the past three weeks, ranging from 75 to 94º F. Skies have been sunny.

There was 1 house fly larvae that was 6 mm and 1 flesh fly larvae that was 26 mm.

Use the table to determine the estimated PMI of the pit bull terrier.

• 3 days

• 4 days

• 5 days

• 6 days

Tags

NGSS.MS-LS1-5

NGSS.MS-LS2-3

NGSS.MS-LS2-4

Case 2:

Police Report: The body of a large pit bull terrier was found inside a walk-in basement at a home in Cary. Maggots were found concentrated in the head and region behind the shoulder. The windows were closed, although the open curtains allowed sunlight to enter, and the air conditioner was set at 72º F.

Weather Report: Daytime temperatures have been variable over the past three weeks, ranging from 75 to 94º F. Skies have been sunny.

What effect did the outside temperature have on the development of the larva?

• It is hot outside so it sped it up.

• It is hot outside so it slowed it down.

• It is hot outside, but the dog is inside and the AC is on so it had no effect.

• It is hot outside, but the dog is inside and the AC is on so it sped it up.

Tags

NGSS.MS-LS1-5

NGSS.MS-LS2-4

Police Report: The body of a large pit bull terrier was found inside a walk-in basement at a home in Cary. Maggots were found concentrated in the head and region behind the shoulder. The windows were closed, although the open curtains allowed sunlight to enter, and the air conditioner was set at 72º F.

Weather Report: Daytime temperatures have been variable over the past three weeks, ranging from 75 to 94º F. Skies have been sunny.

How do you explain that there are only 2 types of flies on the dog?

• The windows are closed so other flies can't get to the dog

• Blow Flies don't like dog carcasses.

• Flies do not come out in when it is sunny outside.

Police Report: The body of a large pit bull terrier was found inside a walk-in basement at a home in Cary. Maggots were found concentrated in the head and region behind the shoulder. The windows were closed, although the open curtains allowed sunlight to enter, and the air conditioner was set at 72º F.

Weather Report: Daytime temperatures have been variable over the past three weeks, ranging from 75 to 94º F. Skies have been sunny.

Do you think the dog died of natural causes?

• Yes, why else would it be in the the basement of a house.

• Yes, flies wouldn't lay eggs in a house any other way.

• No, noone would leave a dead dog in the basement.

• No, the maggots are concentrated in the head and behind the shoulder, not normal openings for flies to go.