Three Oklahoma executions have been halted after a mistake was made with an unapproved drug to be used in lethal injections. The unanimous ruling of the Oklahoma Court of Criminal Appeals to halt all scheduled executions indefinitely came as a result of filings from State Attorney General Scott Pruitt, who asked for time while his office investigates the error.

The error in question was that the drug received was not approved as one of the three-drug protocol for lethal injection executions in the state of Oklahoma. Prison officials realized that their supplier had sent the wrong drug, according to The New York Times. The sealed box arrived on the day of Richard Glossip's execution, and the mistake went unnoticed until the box was opened just two hours before Glossip was scheduled to be executed.

Glossip was granted a last minute stay of execution by Oklahoma Governor Mary Fallin, as previously reported by HNGN.

Potassium chloride, a heart-stopping drug, is approved by the state and was one of the three drugs to be used for the executions, New York Magazine noted. However, the supplier sent potassium acetate to the execution team instead.

The Attorney General asked in the filing to the Criminal Appeals Court for the state to wait indefinitely on the already scheduled upcoming executions of Benjamin Cole and John Grant, in addition to Glossip's rescheduled execution, which was set for Nov. 6, according to The Huffington Post.

The families of the inmates' victims "deserve to know, and all Oklahomans need to know, with certainty, that the system is working as intended," Pruitt said in a released statement.