AURORA, Colo. -- A woman accused of driving drunk and killing two librarians on their way to the airport earlier this year is back in jail.

Sandra Lee Jacobson was arrested and sent to jail in Arapahoe County Wednesday after a fourth motion from prosecutors alleging she was breaking the terms of her bond. Prosecutors say Jacobson, who is accused of two counts of vehicular homicide, was driving illegally.

The motion said that a probation officer saw Jacobson driving a BMW to a leadership and ethics conference in Denver last month.

Jacobson is accused of causing a January accident that killed two librarians from Connecticut, 71-year-old Kate McClelland and 54-year-old Kathy Krasniewicz. The librarians were in a taxi, heading to DIA, when they were sideswiped by Jacobson's pickup truck on Jan. 28. The taxi went off the road and rolled. The women were killed and the cab driver suffered non-life-threatening injuries.

Jacobson, who is from Centennial, has pleaded not guilty in the case. She claimed she didn't know she hit a taxi.

A hearing to reconsider Jacobson's bond has not been set.