At a crime scene, a forensic technician found the body temperature of the victim was 33 degree celcius at 6:00 pm. One hour later, the coroner arrived and found the body temperature of the victim fell to 31.5 degree celcius. The forensic technician determined that the change in the atmospheric temperature could be modelled satisfactorily as 20e^-.02t in the time window of +3 hours starting at 6:00 pm. It is known that the body temperature of alive person is 37 degree celcius. When was the victim murdered?

At a crime scene, a forensic technician found the body temperature of the victim was 33^◦C at 6:00 p.m. One hour later, the coroner arrived and found the body temperature of the victim fell to 31.5^◦ The forensic technician determined that the change in the atmospheric temperature could be modelled satisfactorily as 20e^-0.02t in the time window of ±3 hours starting at 6:00 p.m. It is known that the body temperature of alive person is 37^◦C. When was the victim murdered?