Sean Drenth died instantly and violently on the evening of October 18, 2010, in a quiet alley a half-mile south of the Arizona Capitol building. The cause of death was a single shotgun shell, whose contents entered just under the Phoenix police sergeant's chin and burst through the top of his skull.

A Capitol Police assistant discovered Drenth on his back on the weathered asphalt near 18th Avenue and Jackson. A 38-inch-long Remington 870 shotgun was lying lengthwise on Drenth's body, centered on his chest.The assistant and other first responders noted that the muzzle of the weapon was but a few inches above the contact wound, a detail that continues to loom large to those closest to the case. One detective described the crime scene as "extremely quirky, troubling, totally upside down."

Now, two years after the fact, the circumstances of Sean Drenth's death — one of the most high-profile cases in Phoenix Police Department history — remain shrouded in mystery and speculation. Many close to the Drenth investigation say they expected the Maricopa County Office of the Medical Examiner to rule the manner of Drenth's death "undetermined," not suicide or murder. But in December 2011, pathologist Dr. Robert Lyon concluded that Sean Drenth killed himself. "It was a WTF moment," the sergeant's mother, Diane, says of her initial reaction to Lyon's ruling. (The Medical Examiner's Office continues to decline comment, both to the Drenths and to New Times. Dr. Lyon recently left the office for an unspecified job out of state.)

The shotgun ended up on Drenth's body with the muzzle about four inches from the entry wound, as if the 12-gauge pump-action weapon, loaded with powerful law enforcement ammunition, had little or no recoil. (New Times recently tested a replica of Drenth's powerful shotgun at the Ben Avery Shooting Range. It had a kick of about 18 inches, which was even less than it could be under other circumstances.)

In 2008, the state Attorney General's Office started a criminal investigation of allegations that the cops were paid for security work they didn't perform in full at a Phoenix housing complex. The probe seemed to go dormant until it re-emerged shortly before Drenth's death with a pared-down suspect list of four officers, including Drenth.