WASHINGTON — A former Stafford County teacher who admitted having sex with four high school students pleaded guilty to four charges Friday.

Erica Lynne Mesa, 28, who taught math at Colonial Forge High School, pleaded guilty to two counts of electronic solicitation of a minor and two misdemeanor counts of contributing to the delinquency of a minor, The Free Lance-Star reports.

Four charges were dropped by prosecutors but Mesa faces a maximum of 22 years in prison. She will have to register as a sex offender and has been in jail since her Sept. 29 arrest.

According to the Stafford County Sheriff’s Office, rumors circulated last year about a Colonial Forge teacher who was having sex with students. The school then received an anonymous tip about Mesa’s activities and confronted her about it. She later gave a full confession to authorities.

The charges Mesa was convicted of involved only two of the students, but she admitted to sex with two others, according to evidence. One of the students was under 18 at the time of the sex acts.

Mesa told police that she first had sex with one of the students on his 18th birthday in a local commuter lot. Mesa also reported she had sex with the teens at her home when her husband was away.