These are the second and third arrests on sex-related charges at South Hills High School in less than two weeks

Two California teachers have been arrested on suspicion of having sex with students during two beach trips.

Melody Lippert and Michelle Ghirelli, both teachers at South Hills High School in West Covina, California, were arrested on Saturday after allegedly hosting trips to an Orange County beach where they plied students from the school with alcohol and had sex with them, NBC Los Angeles reports.

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The first of these trips occurred in November and was allegedly organized by Lippert, investigators from the Orange County Sheriff’s Department said.

A group of male students purportedly accompanied Lippert, 38, to San Clemente State Beach, where she gave them alcohol and “engaged in a sexual relationship with one of them,” according to the Los Angeles Times.

A few weeks later, Lippert allegedly set up a second overnight trip and invited Ghirelli, 30, along as well. Both teachers are accused of having sex with students on that trip.

Lippert was arrested on suspicion of conspiracy and contributing to the delinquency of a minor, while Ghirelli faces charges of unlawful sex with a minor, the Orange County Register reports.

“Based on the charges the teachers were booked to, you can make that assumption as to which teacher was with students that were of age and were of not,” Lt. Jeff Hallock told KTLA

“But of course, regardless of somebody’s of age or not, it is very serious,” he continued. “We take these very serious when you’re talking about a student-teacher relationship.”

The two women are scheduled to be arraigned on Wednesday. They have been placed on administrative leave pending an investigation.