Desmond Dejuan Laster was sentenced Friday to four life terms without chance of parole for killing two little boys, their mother and a female accomplice last year.
A jury in March convicted Laster, 22, of four counts of being party to the crime of first-degree intentional homicide, as well as of arson and of being a felon in possession of a firearm.
Laster made no statement during his sentencing hearing before Milwaukee County Circuit Judge Jeffrey Conen.
Evidence presented at his trial showed that Laster and two accomplices - Brittney Robertson, 19, and Anthony Barnes, 24 - went to 23-year-old Rachel Thompson's south side apartment in February 2010.
The group bound and stabbed Thompson, suffocated her two sons, ages 3 and 4, set her apartment on fire and fled with Thompson's 6-week-old baby.
The baby was found unharmed at a church a few hours later.