The Pierce County prosecutor's office says a 32-year-old former school security guard has been sentenced to four years in prison for having sex with underage students.

Prosecutors say that Donte Dwayne Lipscomb had sexual relations with three Stadium High School students between 2009 and 2011. The girls were 16 and 17 years of age.

Lipscomb had pleaded guilty to three counts of first-degree sexual misconduct with a minor.

Prosecutors say Lipscomb pulled the girls out of class and on one occasion had sex with one of them in his office.

In January 2012, school officials contacted police after one of the students alerted them to their sexual relationship.