Officer Spencer O'Bryan had been with the Rapid City Police Department for more than four years when he got off work at 0300 hours on April 18, 2003.

O'Bryan's home was a mere five miles from the police station. And as the house faced the T-intersection of Anaconda Road and East Elk Street, it allowed ample room for O'Bryan to quickly angle his Chevy pickup away from his garage before backing into it. As he had so many other nights, O'Bryan did just that, looking over his right shoulder as he navigated the driveway into his recessed garage.

With the truck ensconced in the garage, O'Bryan turned forward to put the vehicle in park. The glow of his headlights revealed something he hadn't seen before at such an hour: a man walking toward him on Elk Street, a six-cell flashlight in his hand.

The man continued to walk toward O'Bryan's driveway, then suddenly darted to his left where he peeked into a vehicle parked in front of a neighboring house. Just as quickly, the subject made a U-turn and traversed O'Bryan's driveway before disappearing from sight around the corner of O'Bryan's house.

What the hell? O'Bryan wondered.

He turned off his headlights and ignition, then exited the pickup. Having just finished his fourth 10-hour shift in as many days, O'Bryan wasn't exactly up for any last-minute intrigue. But if the sight of a pedestrian on his residential street at this hour of the morning was unusual, the man's actions were downright weird. O'Bryan's investigative impulse took over, and he headed for the front of his house.

O'Bryan guestimated that perhaps seven seconds had lapsed from the time the man had rounded the corner of his house. He looked toward the pedestrian's last seen direction.

Nothing. The view before him was as quiet and undisturbed as any other night. The stranger had seemingly vanished.

The Search

It put an inordinate strain upon O'Bryan's imagination to buy into the notion that the man had not noticed his presence in the garage: The pickup's headlamps had illuminated the man like a spotlight. That being the case, even the most squirrelly guy could have been counted on to adjust his behavior. But not this guy. Now, the man's sudden absence suggested to O'Bryan that his quarry had not only noticed his arrival home, but was now hiding. The hair on O'Bryan's neck stood at attention.

Although he was off duty, beneath his raid jacket O'Bryan wore everything that routinely accompanied him during his tour of duty: uniform, full duty belt, gun, and flashlight. O'Bryan pulled his light and used it to illuminate the front of his house.

At the property line separating O'Bryan's land from that of his neighbor's was a small wooden fence. At three feet high and only five feet in length, the L-shaped configuration was more decorative in nature than anything else. But it was large enough to accommodate a man attempting to hide himself. As O'Bryan's flashlight swept across the fence, the stranger sprang up like a jack-in-the-box.

"Oh, yeah." the man said. "I've got one of those, too!"

O'Bryan found was caught in the beam of the man's flashlight. His sense of discomfort grew acute, but O'Bryan was determined not to allow this situation to escalate into a Mexican stand off. Drawing his sidearm, a model 22 .40 caliber Glock, he aimed at the man.

"I've got a gun, and I'm a cop. Get down on the ground!"

Keeping an eye on the man, O'Bryan moved diagonally to his left, where he could take advantage of the cover near his house. As he did, the man, Alan Liberty, put his flashlight down on the ground and proned himself on the sidewalk.

Beep, Beep, Beep

Somewhat relieved by Liberty's seeming compliance, O'Bryan continued to move across his front yard. The last thing he wanted or needed was to get involved in an off-duty incident in front of his own house. But it was fast becoming apparent to him that such an incident was likely. He keyed his shoulder mic to radio for assistance, but all he heard was a series of beeps letting him know that his radio's battery was dying.

If O'Bryan didn't know any better, he would have thought that the suspect understood the meaning of the beeps and knew that O'Bryan was cut off from backup.

There came a sudden shift in the 27-year-old Liberty's attitude: Cooperation was suddenly no longer an option. Liberty's opening salvo came in the form of an agitated protest that he'd been ripped off and was looking for the people responsible.

It is standard operating procedure for some detainees to distract cops with wild explanations for their behavior. But O'Bryan recognized the ruse and stayed his course, continuing to circle behind Liberty where he could close the distance while keeping himself out of the man's field of vision as much as possible.

O'Bryan was thinking tactically. Liberty was thinking emotionally. He was quickly working himself up, emboldening himself to become more and more non-compliant.

Hoping to get Liberty back in the proper frame of mind, O'Bryan reminded the man that he had a gun. That's when Liberty told him he had something, too. O'Bryan didn't like what he thought Liberty had said, but wasn't sure.

"You have a what?"

"I have a gun, too!" Liberty yelled. "It's on my hip!"

O'Bryan had now drawn within 10 feet of Liberty. Armed with this information, he recognized that he was committed. Whatever else, he also knew that at this distance, he could momentarily forego the use of his mini flashlight.

Call for Backup

Maintaining his aim on the suspect, O'Bryan removed his cell phone from his uniform shirt pocket and dialed 9-1-1. With the line connected, O'Bryan was able to simultaneously manipulate his flashlight and cell phone, cradling the flashlight in his palm while gripping the cell phone between his thumb, index, and middle fingers. This digital dexterity allowed him to maintain cover on the suspect with the Glock in his right hand.

O'Bryan had a growing idea as to just which direction this fight or flight scenario was headed. Hearing the dispatcher's voice on the other end, O'Bryan yelled into the cell phone that he had an armed man at gunpoint even as his verbal tit for tat with Liberty continued.

O'Bryan made the requisite warnings, loud enough to leave no doubt in Liberty's mind as to what might happen, and also to let anyone else who might be awake at this hour of the morning to know what was going on.

O'Bryan wasn't sure what the increasingly histrionic Liberty was doing, or why he was doing it.

Perhaps Liberty was thinking of living up to his name. Maybe he figured he had little to lose. Either way, Liberty was trying to get up. As Liberty pushed his upper torso off the ground and came to his hands and knees, O'Bryan yelled for him to keep his hands in plain sight.

"Show me your hands," he demanded.

"Show me your face," Liberty screamed. "Show me your f**king face!"

Signal 40

Suddenly Liberty spun and made a grab for his hip. O'Bryan had a split second to yell, "Signal 40!" Rapid City PD's code for officer needs emergency assistance into the cell phone before he tossed both it and the flashlight to the ground.

O'Bryan's right arm came up, squeezing rounds from the Glock, as point shooting evolved into a two-handed grip. Amber flashes split the darkness as .40 caliber rounds tore into Liberty's torso, his rightward momentum tossing him into a spin that ultimately put him facedown where he'd started.

What followed struck O'Bryan as even more surreal than everything that had preceded it. A contentious conversation had evolved into shouting, then was suddenly punctuated by a volley of gunfire. O'Bryan had squeezed off five rounds in perhaps a second-and-a-half. And then...quiet. There was no ringing in his ears, just an eerie calm enveloping the scene, punctuated by Liberty's last gasps.

O'Bryan's dying radio suddenly crackled with the transmissions of fellow officers responding to where one of them thought he lived. But they were rolling to the wrong address.

Knowing that any of his own transmissions wouldn't be heard, O'Bryan retrieved his discarded cell phone. Its functionality had been compromised on impact, and he had to take it apart to adjust the battery inside. Once the phone went through its normal startup and he saw that it was ready to dial, he phoned the station and advised of his location, his status, and got paramedics rolling.

One of O'Bryan's rounds had taken out Liberty's brain stem. The man was dead. He lay face down on the sidewalk in front of the house where O'Bryan lived, the gun he'd reached for was still in the pancake holster on his hip. O'Bryan was worried for his fiancée who lay in bed a mere 20 feet away, not knowing what she would make of all the commotion that'd occurred just outside.

Back to Normal

A co-investigation of the shooting was conducted by the Pennington County Sheriff's Department and the South Dakota Division of Criminal Investigations. O'Bryan took a mandatory three days off before returning to work in full capacity.

He went to a critical incident debriefing with the Catharsis Team and had a psychological evaluation with a mental health professional.

O'Bryan was candid, sharing that he had not experienced any personal fallout other than a short period immediately following the shooting when he found himself reliving the moment every night he pulled into his garage at 3 a.m. But he expected as much. And after three weeks, the episodes seemed to lose their clarity and impact.

He also experienced a sense of growing impatience while handling the occasional meaningless calls: Little things became even less significant.

Conversely, it appeared that new significance could be found in some of his citizen contacts. O'Bryan found himself running into Liberty's circle of friends. There was nothing mysterious or threatening about it. It was just the routine byproduct of doing the job, making traffic stops, making arrests, and happenstance.

O'Bryan's life has returned entirely to normal. While he has moved to a new house, he continues to work for the Rapid City Police Department.

Looking back on the situation, he thinks he has some clue as to Liberty's frame of mind. Liberty had been slinging drugs and maybe doing some property capers on the side.

Liberty lived just a few blocks away and was known to traverse through the neighborhood, O'Bryan wondered if the man knew he was a cop long before their paths had formally crossed. In any event, Liberty had proven anything but neighborly, and O'Bryan has no doubt that the man would have taken his life if given an additional second. But as he has since heard anecdotal evidence of the man's suicidal behavior, he suspects that Liberty probably felt that he was in a no-lose situation: He would kill O'Bryan...or O'Bryan would kill him.

O'Bryan noted that as soon as additional officers were on scene, he asked one to check on his fiancée inside the house. It turned out that he needn't have worried. She slept through the entire incident.