K-9 Zena was discovered dead early Wednesday afternoon in the back of her patrol vehicle, police said.
Her handler found her when he went to check on her during a training class at the Criminal Justice Academy in Melbourne.
An active investigation is underway to determine the cause of death and to see if department policies and procedures were followed.
K-9 Zena was donated to the city last August. She was a 2-year-old Belgian Malinois who was trained and newly certified in April for patrol work, police said.