What constitutes a best friend?

Is it someone who comforts you in times of distress? Someone who does not give up on you? Someone who would take a bullet for you?

It really is no wonder dogs are man’s best friend. And the patrol dogs of the Metropolitan Nashville Police Department K-9 Unit are no exception, ready and willing to follow their handlers into dangerous situations every day.

The K-9 Unit has 26 certified police dogs trained for patrol work as well as narcotics and explosive odor detection.

Since the K-9 Unit began in 1973, German shepherds, Belgian Malinois and Labrador retrievers have worked with their handlers to catch the bad guys and sniff out drugs and explosives.

Assistant head trainer, Officer Mark Sydenstricker, has worked with the dogs in the K-9 Unit for 18 years.

“They all have their own personality,” Sydenstricker said. “They have good days and bad days. They’re just like people.”

And they are treated just like people. Recognized as K-9 officers by the police department, the dogs receive as much of the credit and respect as their human handlers.

Passionate about this unit, Sydenstricker started spending time with the dogs and handlers two years before he was officially assigned to it in 1996.

Sydenstricker worked with three dogs before being pulled off patrol to transition to a higher position. Three dogs he loves to talk about.

Neero. Balto. Neeko.

Three dogs, three personalities, three experiences.

Sydenstricker worked with Neero, a single-purpose dog, first. Neero worked as an apprehension dog, which meant he tracked and chased suspects.

Apprehension dogs only investigate felonies, like homicides and bank robberies.

Neero and Sydenstricker worked well together. As a team, they won the U.S.P.C.A. National Quarterly Award in 1997 in recognition of their work tracking a double-homicide suspect.

Neero only lived one week after retirement. He died on Sept. 12, 2001.

Working with dual-purpose dog Balto was a highlight for Sydenstricker.

“Balto was by far my favorite,” he said with a laugh. “He was extremely good at what he did.”

Balto won many awards and successfully completed numerous apprehensions alongside Sydenstricker. He was trained for apprehension and narcotics, and he naturally excelled at both.

While working with Sydenstricker, Balto won the Jimmy D. Anderson award at the regional trials. The team was recognized as the top overall at regional certification.

“That dog was born to be a police dog,” Sydenstricker remembers. “I had a lot of confidence in him.”

Sydenstricker began to work with his third dog, a German shepherd named Neeko, in 2010.

Often, Neeko would rather play with his chew toys than work.

“He was never the alpha dog that the others were,” Sydenstricker said, “but he did his job.”

Forced to retire early because of a stomach condition, Neeko died Dec. 26, 2013.

Officers put a lot of effort into training their K-9 partners and raising them to be the greatest police dogs they can be.

At a young age, every dog undergoes a rigorous training program to prepare for the job. Then, each dog begins yet another training process with a handler. This way, each dog gets certified as an individual and as part of a team with its handler.

Trainers purchase dogs from Denver, Ind., for approximately $8,000 each. Typically, they test 20 dogs before selecting two to bring back to Nashville.

The training process lasts 14 weeks and more than 400 hours to hone skills in obedience, agility and tracking.

After about a month, each dog enters a specialized track in either narcotics or explosive detection in addition to regular patrol training.

Dogs who complete training in explosive detection work with their handlers to conduct security sweeps and investigate suspicious packages.

Dogs in narcotics detection work with all departments, not only the K-9 Unit, to look for drugs.

Trained in hand-signal and voice obedience, building search techniques and methods of pursuit and apprehension, each dog must meet certain standards set by the United States Police Canine Association before certification.

To stay on top of their game even after, the dogs participate in monthly eight-hour training sessions and get re-certified every year.

The dogs’ handlers play a huge role in the success of the K-9 Unit. After certification, each dog works with one handler until retirement.

Usually, handlers get to choose their dogs in order of seniority. Officers take the pairings seriously.

They do not want a louder, more rambunctious dog paired with a more laid-back trainer, as training supervisor Sgt. Danny Hale said. They want the personalities of the dogs and the handlers to complement each other to create the best team possible.

The relationship between the dog and its handler is instrumental to the success of the team, and in most cases, the relationship is strong.

Handlers and their dogs are extremely close. Working together one on one every day, they learn to rely on each other and trust each other’s judgment.

Once the dog retires, it goes home to spend the rest of its life with its partner as part of the family.

In 2012, a city ordinance for the Metropolitan Government of Nashville and Davidson County passed unanimously, stating the City of Nashville would take care of police dogs financially after their retirement.

This includes covering veterinary bills and ensuring that no extra cost comes to the handlers when they bring their dogs home.

It is the only ordinance like it in the country.

All police dogs are cremated when they die, and the police department has an on-site cemetery complete with personalized headstones. Inscribed on each police dog’s headstone is the dog’s name, date active and death date.

The handler’s name is etched on the stone as well.

Neeko’s headstone has just been completed.

As the training supervisor, Hale is consistently surprised by how smart the dogs are.

“They never cease to amaze me, the things they can do,” Hale says.

Hale recognizes what a valuable asset they are to the force. Even after he left the K-9 Unit for a promotion, he came back.

Why?

“This is the only job in the department worth doing.”