LOS ANGELES (CBS) — A third case of inappropriate conduct with a student at embattled Miramonte Elementary School is being investigated, after it surfaced that a teacher’s aide allegedly wrote love letters to a fourth grade students and the report was disregarded.

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The mother of an 11-year-old boy discovered the letters to her son in 2009, from an aide identified as Araceli Luisjuan, according to the Los Angeles Times. The letters were written as farewell notes, because Luisjuan was being transferred to middle school.

One letter read: “When I was writing this letter, I was crying. My heart was breaking into pieces. Oh! I didn’t tell you that I like when you put your arm around my shoulder, and if I told you not to do that it’s because I don’t want to put you in trouble, but I like it…”

The letters are now under investigation by police and Los Angeles Unified School District officials, who have put the school under a microscope since the arrest of two teachers for lewd acts with students.

Veteran Teacher Mark Berndt, 61, was arrested last week after photos of students bound and gagged in his classroom were seen by a photo processing technician. Some photos show cockroaches placed on students’ faces, while others show students being fed bodily fluids on a spoon that tested positive for the teacher’s DNA.

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Later that week, a second teacher was yanked from the classroom then later arrested after being accused of lewd acts against students. Martin Springer, 49, was charged Tuesday with fondling a 7-year-old student.

The school has been closed since Tuesday and the district plans to replace the entire staff in the wake of the allegations.

The mother of the boy says in a July 2009 interview with Hoy, a Spanish-language newspaper, that she reported the letters to her son’s teacher, but was told she could get into trouble for making up stories, according to the Times.

She then tried to report the letters to the Sheriff’s Department, which sent her back to the school. At a second meeting with the mother, son, teacher, Luisjuan and assistant principal, Luisjuan admitted writing the letters, but compared her affection to that of a grandmother for a grandson, the Times reported.

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A district spokesman says Luisjuan was fired in July of 2009, after the complaint was made about her letters. Luisjuan was let go after a meeting with the assistant principal, a counselor and Luisjuan determined she had inappropriate conduct with a child, the spokesman said.