Federal Trial Over Oklahoma's Execution Protocol Starts Monday

Oklahoma's execution protocol will come under scrutiny in a federal trial starting Monday.

Four inmates have been executed since the state resumed executions in October after a six-year hiatus.

John Grant was the first inmate to be executed this period. His death drew criticism and controversy.

Media witnesses reported Grant vomited and convulsed violently in reaction to the drugs given to him.

The Oklahoma Department of Corrections said Grant's execution was not inhumane after it was completed.

Media witnesses at the three other executions did not report any visible issues.