OKLAHOMA CITY (AP) — A review of an Oklahoma execution that was halted midway through says an improperly monitored IV line likely caused problems in administering three lethal drugs.

The report released Thursday by the Oklahoma Department of Public Safety noted that a paramedic and physician inserted the intravenous line in Clayton Lockett's groin after failing to find a suitable veins in his arms, legs, neck and feet.

The report says the IV site was covered with a sheet and not monitored until the physician saw swelling larger than a golf ball.

Lockett's troubled execution in April led Oklahoma's governor to issue a moratorium on all executions until the review is complete.

The review also recommends more training for prison staff and medical professionals involved in executions.