Really depends on angle of entry, but it is perfectly possible to shoot someone from the front and have an angled intry into the skull behind the ear, especially if the perp was starting turn his head even slightly, beginning to scan for which direction to run. Behind the ear doesn’t necesarily mean in the crease behind the ear.
I know, but it sounds more like he was turning to run ( again) or was running away.
Either way it doesn’t look good for the cop’s credibility and/or judgment.