Master Patrol Officers David Ashley, left, and Lorin Johnston talk about their feelings and how they were affected by the tatal shooting of Sgt. Tim Chapin a year ago. Ashley and Johnston were among the first officers to respond to a robbery call at the U.S. Money Shops on Brainerd Road on April 2, 2011, where Chapin was killed in a shootout.

Chattanooga Police Sgt. Timothy Chapin

Chattanooga police officer Lorin Johnston will never get over the events of April 2, 2011.

A patrol officer for 17 years, Johnston has responded to murder-suicides. Been shot at. Seen the death of the most vulnerable -- children and the elderly.

And sometimes he imagines things in worst-case scenarios. He recently suffered through a nightmare in which he responded to a traffic crash.

"I was calling for help and no one was coming," he said.

Officers remember the people they try to help. The people in traumatic situations that Johnston has handled stay with him, visit him in his dreams.

Sgt. Tim Chapin is a regular visitor.

Along with Chapin and other officers, Johnston, 47, responded to a robbery call on April 2, 2011. Chapin, 51, was gunned down by the suspected robber; Johnston was injured.

Jesse Mathews, 26, has been arrested and charged with murder in Chapin's death. Police believe Mathews, a wanted fugitive from Colorado, planned the robbery to continue his run.

A year later, when Johnston is at home in North Chattanooga, he can be himself -- a sweet, sensitive guy who jokes around. He recovers from the stress he deals with on the job. He prepares for his next work week. But when Johnston, tall and burly, dons the blue uniform, it's back to business.

"The days off go a lot quicker than they used to," he said. "In our line of work ... when you put on the uniform and sit in that car, you're on the edge."

Anything can happen.

He still remembers being called to a head-on collision in the early 2000s on Hixson Pike involving a UTC student. He unfastened the young woman's seat belt and slid his hand behind her back to stabilize her. He still can hear the single labored breath she took before she died.

"I felt her last breath," he said, his voice dropping. "That was it."

But despite the things he has seen on the job, it's Chapin's death that has affected him the most.

"After incidents like that, Tim's was so traumatic all the way around compared to other things I've been through," Johnston said, sitting at his kitchen table. "You find yourself thinking about it and don't even realize it."

After the shooting, Johnston took a week off, following department policy. He initially went back to Delta team, which covers Brainerd, the community where Chapin died.

The memories proved to be too much for him and for Officer David Ashley, 42. The two had been with the department since 1992, and were the first to respond that Saturday morning to the armed robbery call at the U.S. Money Shops on Brainerd Road.

After the shooting, not a day went by without both men passing the spot. And each time they did, they thought of Chapin's death.

"Since the anniversary has come around, it's gotten more difficult in the last couple of weeks," said Johnston, sitting with his wife, Mitzi, in their home last week.

As he speaks, he holds back tears building in the corners of his eyes. His voice softens slightly as he recalls that day.

The same flood of memories happens to him, Ashley said, standing near his patrol car last week while at a call on East 10th Street. Sunglasses mask emerging tears that he manages to fight back. He lowers his gaze to the ground as he talks.

"It brings up a lot of emotions for us. A lot of people don't understand what we went through that day. I wouldn't wish this on anyone," he said, sorrow filling his voice.

After the shooting, Johnston and Ashley transferred to Bravo team, which handles the downtown Chattanooga area.

"I guess the best way to look at it is, you need to make new memories to try to put the bad memories aside. ... A change ... will help you, but you never forget," Johnston said.

Chattanooga Police Chief Bobby Dodd said it's standard to offer transfers to officers involved in fatal shootings.

"We move them to a different location to give them different surroundings," he said, and both men seem to be "transitioning well."

Still, both officers think about how the events unfolded the day Chapin was killed. Ashley's left arm is tattooed with a blue-and-black cloth draped over a cross and Chapin's badge number, 554, stripped across the top. He got the tattoo not only to honor Chapin but also because the incident changed his life.

"It's one of those things where you try to move on with your life, but you never forget," Ashley said.

NIGHTMARE

It's an officer's worst nightmare. With his service weapon raised, he fires at a threatening assailant, but the man just keeps coming. The bullets fall harmlessly to the ground.

It's similar to what Johnston recalls from the day Chapin was shot: the assailant, face covered, firing from inside the pawnshop at him, and him returning fire. But the shooter, who police later found was wearing a bulletproof vest, just kept coming.

Johnston blocked the robber from the getaway vehicle -- where police would later find other firearms, including an AR-15 assault rifle -- held his position and returned fire. And fired. And fired. He hit the center of the robber's body, a shot that should have taken the man down but didn't.

Johnston, who also was wearing a bulletproof vest, was struck in the back as he went for his AR-15 in the trunk of his patrol car. His vest stopped the round.

The suspect continued firing, then retreated inside the store before escaping through a side door toward Old Birds Mill Road.

Chapin pulled up in his patrol car and drove after the suspect. After 26 years on the job, the sergeant was used to going hands-on to capture suspects trying to get away.

"He was backing up his men," Johnston said.

Chapin hit the suspect with his Ford Crown Victoria patrol car and knocked him to the ground. A single gun skittered away.

Chapin fired his Taser into the suspect's body. It didn't stop the man, who unzipped his jacket and pulled out a second gun. Chapin pulled his weapon and the two exchanged shots until a round struck Chapin in the head, killing him.

Other officers rounded the corner and took the wounded robber, later identified as Mathews, into custody.

Johnston didn't even notice he'd been shot until he was kneeling at Chapin's side.

"Check my back. There's something hurting my back," he said.

Another officer asked, "Are you hit? Are you hit?"

"I don't know, just check my back," he said.

The others stripped Johnston's uniform shirt and vest away and found a bullet hole in the vest. Doctors later told him his lung was bruised.

The officers told him to lie down to wait for an ambulance.

Sprawled on the ground, he turned his head toward Chapin's lifeless body. He reached out and clutched the sergeant's limp hand in his own.

"I knew he was gone," Johnston said.

Other officers stayed with Chapin's body, placing their hands on him. No one was ready to let go. Master Patrol Officer Marcus Easley, who retired shortly after the incident, led them in prayer.

Altogether, five officers were on that call. Mark Bender responded with Chapin, Johnston and Ashley, and Jonathan Brock, who was working a nearby off-duty security job, came in toward the end.

Bender, Johnston and Ashley all received the Medal of Valor, the department's highest honor.

A FALLEN OFFICER

When former Assistant Chief Tim Carroll received word of an officer shot on April 2, 2011, he had his stepson, Officer Terry Barnes, take him to the scene. Barnes was on his lunch break, watching a children's ball game with Carroll at a nearby field.

Carroll, who wrapped up a 30-year career with the police department last week, at first didn't believe Chapin was involved in the shooting.

Carroll once was married to Chapin's sister, Lisa.

When Carroll arrived at the scene, the first thing he saw was a small group of uniformed officers in a huddle, peering down.

Carroll walked past an ambulance as paramedics worked on the assailant inside.

"As I get closer, one of the officers was saying Tim's name and rubbing Tim's back. I'm thinking, 'We're waiting on another ambulance. He's conscious and alert.' Then I got around and saw it was Tim and he was dead," Carroll said.

Officers are trained to remain objective and removed even in the worst of circumstances. They investigate. They take notes. They stay calm. They become numb to tragedy they see every day in their jobs.

That works until something happens to one of them.

"I just felt hopeless and helpless," Carroll said.

Even so, he had to tap into that training, push those emotions down, get the job done, cry later.

"I said, 'Guys, you're not going to understand this. It's a crime scene. That's not a soul anymore. We've got to make sure that bastard in that ambulance, if he lives, doesn't do this to anyone else,'" Carroll said. "I said, 'Just back up away from here.' Of course, they didn't want to go. I understand it."

Officers lingered with Chapin's body, unable to say goodbye, but eventually, slowly, they began to disperse.

During his career, Carroll worked about 450 homicide investigations in Chattanooga, seeing gruesome scenes. Police often give the news to people that a loved one has died.

For the most part, he was never bothered by his job, he said.

"I've seen everything in this ... planet and that [Chapin's death] bothers me. I still have horrible nightmares," he said. "I still can't believe it."

After the shooting, when the Chapin family had gathered at Tim Chapin's house, Carroll and Dodd laid out what went down on the call. Dodd couldn't make it through the story, breaking down and crying.

Carroll took over. Facing Chapin's family, their mouths agape and eyes wide open, he pressed on.

"That's the toughest family notification in my damn life," Carroll said.

Since the shootings, the relationship dynamics have changed between the officers and their loved ones.

"It's one of those things I kept replaying in my mind, and I wasn't even there," Mitzi Johnston said. "I know it's a dangerous job, but I've never worried he couldn't take care of himself."

On April 2, she texted Johnston about cooking out that night. He never responded. For years, she never worried about him if she couldn't reach him immediately. Now if she can't reach her husband by phone, she panics. She calls his co-workers. She phones police dispatch.

Johnston must take time out to call or text her to say he's unavailable.

And when he's at home, she can sense when his mind wanders back to that day.

"I can look at him and just know," she said. "We both still have nightmares, but we still get up and go to work."

DEALING WITH GHOSTS

As time passed and Johnston started sharing the story of what happened, he said, "It helps me and hopefully, it will help someone else."

The scene at the pawnshop replays in his head. Sometimes it starts at the beginning, sometimes midway through, sometimes toward the end. It always ends the same.

"Go ahead and let it play out in your mind and deal with it," he said. "The more you do that, the easier it gets."

But it's a haunting image.

"Seeing the guy shoot at me and me shooting back at him, and just what I was looking at," he said.

As a way to help Johnston cope, his wife asked him to draw what he saw that day. It was a terrifying armed bandit with his face covered, she said.

"And then I would stop," Johnston said, when dreaming about the incident. "And I would second-guess myself."

He still asks: What if?

Carroll doesn't.

"Lorin and David were going through tough times about it -- 'If I had done this or if I had done that.' I said, 'You know what? The only person who did something wrong was Jesse Mathews. Not Lorin. Not David. It's Jesse. Y'all did exactly how you were trained to do.'"

POLICE BROTHERS

Earlier on the morning of April 2, Delta officers had gathered for coffee as they normally did inside Starbucks at 5610 Brainerd Road, just down the street from where the botched robbery unfolded.

Now a year later, a picture in a golden frame hangs inside the coffee shop. It's a portrait of Chapin in a dress uniform next to an American flag. On any given morning, the officers he used to oversee still get together at a table near the photo, drinking coffee before they must answer calls as part of Delta team.

Sgt. Danny Hill, who was one of Chapin's best friends, sits among the officers. He was off duty the day the shooting happened and has decided to stay with his team.

"I didn't want the guys to lose another sergeant by me moving," he said.

Hill now has a large tattoo in Chapin's memory adorning his right leg. It reads, "Rest in peace, my brother."

In many ways, the two were brothers.

Hill, a 27-year department veteran, went through the academy with Chapin. They were the two sergeants on duty for the Delta team, working day shift.

As young men in their 20s, they were roommates for nine years until Chapin married his wife, Kelle.

On April 2, Hill, along with his wife, Tara, went to find Kelle Chapin to break the news to her about her husband's death.

He thinks of that day often.

"It's still tough. You get to drive by it every day," he said, standing outside the Starbucks one morning last week. "It's just something you don't forget."

For the officers who walked away, still alive after the shooting, friends sometimes have a hard time finding the right words to say. There's an awkward silence.

"They look at you and wonder, 'What's going through his mind?'" Johnston said.

"That's just human nature," his wife said.

On Thursday, Ashley and Johnston were both sent to a robbery call downtown. It turned out to be nothing, but it made them think of last year.

After an officer survives a call like the one that left Tim Chapin dead, the risk seems even greater to the officers who were with him that day.

"When you get out of the car, you get this irky feeling," Johnston said. "You get out and go, 'OK, what's going to be presented to me today?' Because you never know."