Complex sentence: Serpico was shot in 1971 during a drug raid that his colleagues failed to cover him on, survived and testified to the Knapp Commission that year and retired on a disability pension in 1972, lived abroad until his quiet return to the U.S. in 1980.
Split into simpler sentences: Serpico was shot in 1971 during a drug raid that his colleagues failed to cover him on. Serpico survived and testified to the Knapp Commission later in 1971 and retired on a disability pension in 1972, living abroad until his quiet return to the U.S. in 1980.