(CBS) — The principal of a Chicago public high school credited with a resurgence has resigned amid an investigation.

One parent tells WBBM she experienced some of what allegedly led to the principal’s ouster.

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CPS won’t say why it had Susan Lofton removed two weeks ago but sources tell WBBM she was allegedly lowering test scores of special needs students to keep them out of Senn High School’s magnet fine arts program.

Laurie Hasbrook says during a 2012 meeting, Lofton strongly discouraged Hasbrook from sending her special needs student to Senn, his neighborhood school, by saying they didn’t have the resources to meet his needs.

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Hasbrook’s son, who she says has an intellectual disability that puts him at roughly a fourth grade learning level, was accepted into a special education high school.

Hasbrook says she hopes now that Lofton is gone, Senn’s administration will devote more resources to special needs students but in light of CPS budget cuts has serious doubts about that.

WBBM was unable to reach Lofton for comment.

CPS said last week about Lofton’s removal it has high standards for its school leaders, and takes any allegation of impropriety very seriously.

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A spokesman said “While we do not comment on personnel matters, our focus is on ensuring this school has a strong leadership team in place to effectively support the school’s students and staff.”