In December 2007, the body of a man was found on the waterfront of a lake in the outskirts of a rural area near Bonn, Germany. He had been reported missing about a month before the finding and was reported to have left a mental health institution without being dismissed. His body was clothed and partly hidden under bushes.
In the autopsy report it was stated that no typical signs of decomposition were present, and livor mortis could be observed only sparsely. The cause of death was bleeding to death after cutting the throat. Furthermore, it was concluded to be a suicide.
Caption
During the investigation of the oral cavity, several blowfly larvae of different sizes were revealed. During autopsy, living larvae were collected and placed on a feeding substrate to rear them at constant 25°C (77°F) until adult flies would emerge. This was done for two reasons; first, it is easier to identify the species based on the adult fly; and second, it would reveal the remaining developmental time until pupation and thus make a larval age calculation more reliable.
The species was identified as Calliphora vomitoria. Ames and Turner (Med Vet Entomol 2003;17:178–186) published an ADH value of 5638 from egg to pupation for this species. Analyzing the daily temperature measurements of the nearest weather station and calculating a daily mean temperature accounted for the temperatures that influenced larval development during the time the body lay at the lake. For this calculation it was essential to take into consideration that on several days the daily mean temperature fell under the lower developmental threshold.
Fig.2 In the autopsy report it was stated that no typical signs of decomposition were present, and livor mortis could be observed only sparsely.
Calculating the ADHs using the mean ambient temperature and excluding days with temperatures below the developmental threshold revealed as a starting point of larval development a time frame of 1 or 2 days after the man went missing. Usually, insects of central Europe are not overly active in November and December because the temperatures are very low. However, on the days the man went missing, it was unusually warm, which may have provoked certain insect activity.
The results of the autopsy concluded a much shorter PMI that could have led to the question what happened between the days the man went missing and death occurred. However, the results of the entomological analysis supported the much more likely scenario that he had left the mental institution and killed himself shortly afterwards.
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