The woman who plowed through a crowd of people with her car Saturday night will no longer be working as a receptionist in the office of Washington, D.C., Councilman Marion Barry.

Barry, the former mayor, terminated a contract with the company who provided Tonya Bell as a temporary employee for his office.

"Needless to say we are greatly saddened by the incident not only because of the tremendous pain and suffering of the victims, but also because our office relied on the integrity of your screening procedures in agreeing to the placement," Barry wrote in a letter sent to NAI Personnel, the employment agency.

Forty people were injured after Bell drove through a street festival with her Volvo. Bell had been "smoking crack all day long," Police Chief Cathy Lanier alleged.

"The behavior of your employee, although outside of work, indicates that you may not have properly investigated her background prior to placing her in our office," the letter reads.

Bell, of Oxon Hill, Md., was treated for an ankle injury and was in police custody pending arraignment Monday, police said. She was preliminarily charged with aggravated assault while armed. The "armed" designation is because she used a vehicle.

Authorities believe Bell was going about 70 mph when she tore through Unifest, a church-sponsored street festival in southeast Washington. Witnesses described a scene of mayhem after Bell sent people and strollers flying, leaving debris and injured bodies strewn in her path.

Thirty-six people were taken by ambulance to eight hospitals after the incident. Still, others drove themselves. A 4-year-old boy with a broken leg was still hospitalized, but was expected to be discharged Monday, said Emily Dammeyer, a spokeswoman at Children's National Medical Center.

FOX News' Caroline Shively contributed to this report.