A 31-year-old Florissant woman hanged herself in the St. Charles County jail Monday night, officials said.

Annie Wilson was found in her cell about 10:30 p.m. when her cell mate was brought back to the cell after watching television. Wilson tied a bedsheet to the ladder rung on a bunk in her cell and wrapped it around her neck, said county spokesman John Sonderegger.

Sonderegger said guards check on each cell every 30 minutes between 10:30 p.m. and 6 a.m. During other hours, inmates don't have to remain in their cells and can use a day room.

Wilson had been in custody in the jail since early Saturday on warrants for writing bad checks in St. Charles and Lincoln counties. She was separated from her husband and had four children, Sonderegger said.

The county Sheriff's Department was investigating the death.

Sonderegger said Wilson was given a drug and alcohol screening before she was put in her cell. Inmates who don't pass the screening are sent to a cell block for suicidal prisoners.

This is the first suicide reported at the county jail since April 2009, and Wilson is the first female to commit suicide in the jail, Sonderegger said.

Five suicides occurred there between 2006 and 2009. All of those inmates used something from their cells to hang themselves. Larry Crawford, the county's current director of corrections, was hired in October 2009.