Complex sentence: He was then head of the homicide division from 1939 until his retirement in 1944 at which point he became the Chief of Police at Kennywood, an amusement park in neighboring West Mifflin, Pennsylvania.
Split into simpler sentences: He was then head of the homicide division from 1939 until his retirement in 1944. In 1944, after retiring from the police force, McQuaide became the Chief of Police at Kennywood, an amusement park in neighboring West Mifflin, Pennsylvania.