ARVADA, Colo. -- A longtime middle school teacher allegedly took her own life during an investigation into a physical relationship between her and a student.

Gretchen Krohnfeldt, 47, took her own life on Tuesday, according to a family member who spoke to CBS Denver. Police sources say Krohnfeldt killed herself in front of police officers who were approaching her home in Arvada, Colorado, to question her in the investigation.

Krohnfeldt was placed on leave Monday night from her position as a teacher at Drake Middle School in response to an investigation by Arvada police and the Jefferson County Sheriff's Office.

On Monday, the Jeffco Sheriff was made aware of a possible inappropriate relationship between a female employee at the school, later identified as Krohnfeldt, and a male student.

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CBS Denver reports an employee witnessed an inappropriate interaction between Krohnfeldt and the student months ago but only reported it to authorities on Monday.

According to Arvada police, the relationship allegedly began when the student attended Drake Middle School. That student is now a high school student in Arvada.

Drake Middle School in Arvada, Colorado. CBS Denver

During the investigation it was alleged that a physical relationship occurred between the two in Arvada, where Krohnfeldt lives. Sources say the alleged relations took place at Krohnfeldt's Arvada home.

The matter of Krohnfeldt's death is being investigated by the coroner. Krohnfeldt had three children.

Grief counselors were available at the middle school on Wednesday and would be there for the rest of the week as a resource for both students and staff.

The school sent a letter home to students saying, "Our hearts go out to her family at this painful time."