A Palm Beach County man has pleaded guilty to the fatal shootings of four men over a three-day span and has been sentenced to 40 years in prison.

Derek Dixon pleaded guilty to four counts of second-degree murder Wednesday and gave a short apology to the victims' families.

Authorities say the slayings were motivated by revenge.

In the first incident, 23-year-old Reynold Barnes and 26-year-old Eddie Gibbs were found dead in a car near Palm Beach Mall.

Three days later, 22-year-old Turner Norwood and 22-year-old Ali Jean were found shot to death in a car east of the mall.

Dixon's sentence will run concurrently with a 40-year prison term he's serving for carjacking and possession of a firearm by a convicted felon.