Clayton Lockett takes over 40 minutes to die as execution goes wrong. 

An Oklahoma death row inmate died of a heart attack Tuesday night more than 40 minutes after his execution was halted because the lethal injection of three drugs was botched. The execution of a second convicted murderer was postponed. Corrections Director Robert Patton halted the execution of Clayton Lockett about 20 minutes after the first drug was administered. He said there was a vein failure that prevented the deadly chemicals from reaching Lockett.

Witnesses said Lockett writhed and convulsed on the gurney, shaking uncontrollably.

Read it at USA Today.