Lake County prosecutors expanded their case Wednesday against a Lakeport couple accused of recruiting a high school student to become a prostitute, charging them with selling three more victims into the sex trade.

One of the four victims was a minor, allegedly placed into prostitution in 2006 when she was 17, Lake County District Attorney Don Anderson said.

Investigators are interviewing at least two more potential victims of human trafficking — one a minor and the other a young woman who lives in Colorado, Anderson said.

Sam Lindsey Massette, 37, and his wife, Krystina Marie Pickersgill, 27, remain in Lake County Jail on $1 million bail. They are scheduled to be arraigned Tuesday in Lake County Superior Court.

Massette, who has a bachelor’s degree in psychology from Marymount California University, had previously worked at a Colorado nonprofit dedicated to counseling survivors of violence, particularly domestic and sexual abuse. Massette also interned at Crestwood Mental Behavioral Health Clinic in Angwin in 2015 for one day a week and under constant supervision, according to company spokesman Larry Kamer.

Massette used threats of violence to control his victims and frequently bragged about having killed someone, prosecutors said. Investigators think Pickersgill might also have been a victim at one point.

“We really would like to know her side more, more about how she came about being involved with this,” said Anderson.

Pickersgill was unemployed at the time of her arrest, but Anderson said she was illegitimately employed “hooking for him.”

Two Jaguars and two Mitsubishi vehicles owned by the couple and parked in front of their Lagoon Drive home were financed by trafficking and were confiscated, Anderson said. Massette has not filed taxes in several years, and prosecutors are considering tax-evasion charges.

Massette and Pickersgill recruited girls in high school and took them to San Francisco to be sold as prostitutes, according to investigators.

The first alleged victim told investigators she became friends with the couple on Facebook while she was in high school. Massette eventually persuaded her to send him nude photos of herself, and the girl later moved into the couple’s home, Anderson said. After she turned 18, the couple allegedly took her to San Francisco and made her work as a prostitute, Anderson said.

The amended complaint charges Massette and Pickersgill with human trafficking, pimping and pandering two additional victims.

Massette is charged with human trafficking a fourth victim, the 17-year-old minor in 2006. If convicted of the offense, Massette could face a sentence of up to 15 years to life in state prison.

This is the third case of human trafficking prosecuted this year in Lake County.

“We know that there are other victims out there currently working for other traffickers and that several other women and teenagers are being recruited for this purpose,” Anderson said. He asked anyone with information about trafficking or soliciting teenagers for prostitution to contact the District Attorney’s Office.

You can reach Staff Writer Meghan Herbst at 707-521-5250 or meghan.herbst@pressdemocrat.com. On Twitter @Megeherbst.

EDITOR'S NOTE: Sam Massette attended Marymount California University. The name of the university was incorrect in a previous version of this story.