MILWAUKEE (CBS 58) -- Nineteen-year-old True Serwin was sentenced in his role in armed robberies of Milwaukee mail carriers.

Serwin was sentenced to 8 years in prison. 

Three other individuals were charged in their roles with the robberies. 

Eighteen-year-old Jose Federico-Flores was previously sentenced to four years in prison after he pled guilty to his role in the robberies.

Nineteen-year-old Jesse Lee Hernandez was previously sentenced to six years in prison.

Twenty-two-year-old Christian Gustavo Lara-Maldonado previously was sentenced to 7 years in prison. 

Prosecutors said each participated as a party to a crime in the robberies, either by directly participating, aiding or conspiring to commit the crimes. A criminal complaint alleges Hernandez provided a gun, Serwin acted as the driver, and Lara-Maldonado and Federico-Flores participated directly in both robberies. Investigators say all four suspects were in the same car, and together they sold a key taken from a mail carrier.