Texas police have accused a 38-year-old former kindergarten teacher of having sex with four high school boys - two of them at the same time - PEOPLE confirms.

Heather Lee Robertson of Lufkin, Texas, was arrested Saturday and allegedly admitted to the acts, according to her arrest affidavit, which was obtained by PEOPLE.

She is charged with four counts of having an improper relationship between an educator and a student and had multiple trysts with two of the students, court records claim.

An investigation into her conduct began on Thursday, and officers spoke with all four students, according to the affidavit.

The first boy allegedly told investigators he had started chatting and sexting with Robertson through Snapchat, the affidavit states. In time, she allegedly invited him over for sex.

He brought a friend, leading to a group sexual encounter at her home, court records allege. The second student confirmed the account of the first.

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Officers then spoke to two other students, who also admitted to having sex with Robertson on a few occasions, according to the allegations detailed in the affidavit.

They claimed they would sneak out of their houses and Robertson would pick them up and take them back to her apartment to have sex before driving them back home.

When confronted by police, Robertson allegedly admitted to the illicit affairs, court records show. She “advised she recently became a heavy drinker and would sometimes not remember the details of the sexual encounters with the students,” the affidavit alleges.

Robertson remains in custody on an unspecified amount of bail and it was not clear if she has entered a plea.

The school district where Robertson worked did not return PEOPLE’s request for comment. But the superintendent told the Lufkin Daily News on Friday that Robertson resigned from her job on Thursday, hours after school officials learned of the accusations.

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Attempts to reach her defense attorney were unsuccessful.

This article was originally published on PEOPLE.com