At the end of a stone path near a quiet stream sits a cemetery for police K-9s. Some died of old age. Others were killed in the line of duty. For all of them, a marble plaque near the entrance reads, "The valiant acts of those buried here are known only to God and to us."

But more than a hundred others learned of those valiant acts Thursday during a graduation ceremony for the St. Paul Police Department's regional K-9 class.

Around 100 people applauded 16 graduates and their K-9 partners, who work for police departments including those in Roseville, Edina and Duluth. Others traveled from afar, hailing from Sawyer and Washburn counties in Wisconsin. St. Paul Police Chief Axel Henry presented graduation certificates. Some K-9s barked as their handlers' names were called for graduation. Other dogs wagged their tails, panting in the heat and glancing at orange tennis balls tucked in their partners' uniforms.

Thursday's ceremony also marked 30 years since St. Paul Police Officer Timothy Jones and his K-9 partner Laser were killed. Jones and Laser were searching for a man who killed Officer Ron Ryan Jr. that day and were killed by the same man. The department's K-9 training center was named in their honor.

Head trainer Brady Harrison said many of the dogs were born in Europe before being flown to a training center in Florida. Officers paired with them in December, launching a 15-week training class.

After the ceremony, the K-9s sat at attention during a series of demonstrations, glancing at handlers who told them to investigate areas and sniff for gun parts. In one drill, officers threw smoke bombs and drew fake guns before announcing themselves as members of the K-9 unit. One of the dogs leapt forward, kicking dirt behind as they jumped over construction equipment and locked teeth onto an officer pretending to be a criminal.

Harrison said many police departments had no K-9s until after 9/11. Since then, Harrison said the dogs have played a vital role in policing and keeping officers safe.

"Our dog is the early warning system so that we can make a better plan and slow things down so we are safe. And, all in all, if that suspect does want to give up, they're safe," Harrison said, adding that many graduates will build lifelong connections: "These guys will be friends into their 80s and 90s just because of this small niche of K-9. ... It's just a bond that never gets broken."