A forensic autopsy is performed if the death seems suspicious or the cause of death is believed to be a criminal matter.  In some jurisdictions, a forensic autopsy is also performed if the person who died wasn't under the care of a physician for a known medical condition, if the person was under medical care for less than 24 hours, or if the person died during an operation or other medical procedure. A specially trained doctor called a forensic pathologist performs a series of internal and external tests and examinations, which include weighing and measuring the internal organs, and checking for the presence of drugs, alcohol, and infectious diseases. It takes about two to four hours to complete a typical forensic autopsy, although it can take longer if special tests are required. The results of all tests must be in before the medical examiner can sign the death certificate and the body can be moved to the funeral home.