An Apple Valley gang member pleaded guilty Friday morning to the first-degree murder of a 17-year-old Sultana High School football player.

Mathew James Santos, 19, pleaded guilty to shooting and killing Steven Gonzales.

The guilty plea makes Santos the third of four defendants to plead guilty. Santos is expected to be sentenced to 25 years to life in prison Oct. 27.

Santos was only 16 when he shot Gonzales in the chest with a shotgun at a birthday party in the 23000 block of HoHoKam Circle in Apple Valley. Officials confirmed that Gonzales was not involved in any gang-related activity.

Tomoya Shimura may be reached at or (760) 955-5368.