Indianapolis police are investigating the death of a 4-month-old infant on the east side of Indianapolis. Officers were called to the 5900 block of East Washington Street about 1:45 a.m. Tuesday on a report of an unresponsive child. Detectives are questioning the parents of the infant. A friend of the family said the infant was left unattended in a car seat inside the home as the father slept. When the father woke up, the car seat was tipped over and the infant was no longer breathing.