A whistleblower report on possible wrongdoing by a Healthcare.gov subcontractor has Missouri’s senior senator demanding answers.

U.S. Senator Claire McCaskill is calling for a thorough investigation into claims the Wentzville, Missouri processing facility pays its contractors to do no work for days at a time.

McCaskill, Chairman of Senate Subcommittee on Contracting & Financial Oversight, sent a letter to the U.S. Department of Health and Human Services Inspector General.

In the letter, the Missouri Democrat calls on the administration to, “evaluate these claims and, if warranted, undertake a thorough investigation,” into the contract by Cognosante, a subcontractor to the prime contractor Serco.

McCaskill also outlined claims made to the Subcommittee by one whistleblower, who worked in customer support at the processing facility for approximately two months in 2013, that the contractor “repeatedly called her in to work and paid her on days when the company was aware that its employees would not be able to do work due to problems with the Healthcare.gov website.”

Earlier this week, KMOV-TV in St. Louis reported similar whistleblower allegations at the same Wentzville facility. Specifically, it reported that employees were told to “sit at their computers and hit the refresh button every 10 minutes” waiting for applications to process. KMOV’s source also alleged that, even though the employees sit idle for days at a time, Serco is continuing to hire new employees because its payment is linked to the total number of employees working at the facility.