Grove wasn't afraid to prosecute people, but he tried to educate them, too, said Stoner, who had shared his 180-acre hunting ground in western Adams County with Grove for the last three years.
Stoner dropped into a chair Saturday at the Fairfield Inn across the street from where Grove once lived, disturbed about losing his friend, shaking his head and calling the crime "useless" and Grove's death "senseless."
Police say Grove, a Pennsylvania State University graduate deputized as a conservation officer in 2008, was shot in the head by Christopher L. Johnson, 27, of Fairfield, during a nighttime altercation over illegal deer hunting. Johnson is held in the Adams County jail, charged with first-degree murder.
Grove is being remembered as the first conservation officer slain in Pennsylvania in the line of duty since 1915. Gerald Feaser, a spokesman for the Pennsylvania Game Commission, said that the funeral would be Sunday in Waynesboro and that conservation officer delegations from almost every state were expected to attend.
Grove's unusual balance of compassion and courage made him an ideal law enforcement officer during his brief career, said Stoner, 72, a retired high school coach and guidance counselor.
When Stoner met Grove six years ago at the Rouzerville Fish & Game club just west of Gettysburg, Grove - bookish, slightly built, about 5 feet, 9 inches tall and 140 pounds - was working as a deputy conservation officer, a volunteer eager for a chance to share his knowledge of hunting and safely manage the state's deer.
Stoner didn't think Grove would make it in the rough-and-tumble world of law enforcement, he said.
But after Grove completed a nearly yearlong training course, a metamorphosis occurred, Stoner said.
"He really grew confident and was dogged in his pursuit of offenders," he said. "Soon he was solving crimes right and left."
Feaser said he remembered when Grove was selected to attend the wildlife conservation officer training class in 2007.
"You'd think he won the lottery," Feaser said. "He had a smile on his face all the time. He was made to be a conservation officer."
Patrolling the back roads and forests of Pennsylvania in search of illegal hunters is just a part of a conservation officer's job, but it occupies significantly more time in the fall.
Poaching has long been a problem throughout the state. With one million hunting licenses issued each year, Pennsylvania has more legal hunters than any state except Texas. An estimated 1,000 cases of poaching - including people caught hunting at night or out of season, using spotlights, or shooting from vehicles - are prosecuted in the state each year. But that number represents only a small fraction of illegal hunters, state game officials say.
It was a call about night hunting near several luxury houses on multiple-acre tracts about two miles from Gettysburg National Military Park that put Grove in harm's way Thursday night.
He stopped two men in a pickup truck about 10:30 p.m., shortly after they had killed a buck in a cornfield. Grove was trying to handcuff Johnson when, police say, Johnson pulled out a .45-caliber handgun, touching off a "ferocious firefight" that ended with Grove lying on the ground with a bullet in his head. He was pronounced dead at the scene. Johnson was apprehended Friday morning at a hunting cabin several miles away. He was taken to a hospital with a gunshot wound to a hip.
Adams County District Attorney Shawn Wagner said Friday that "there is a very great possibility, if not certainty, that we will seek the death penalty."
Feaser said the fact that there had been only a handful of altercations with game officials in the last several decades didn't diminish the threats to law enforcement officers patrolling alone, often at night, in remote areas. And, he said, the people they are looking for are nearly certainly armed.
Chalmer Helm of York Springs, who served as a volunteer deputy conservation officer for 20 years, said he had witnessed generations of poachers in action.
"You'd pick up a guy, and then a few years later you're picking up their son or grandson," Helm said. "Some people go insane when they see big deer. They think being given a hunting license gives you a privilege to do whatever you want."
Stoner said Grove, who was single, had never tried to bully people when he caught them, but had been relentless in the cat-and-mouse chase of poachers.
"He made a difference in his young life," he said. "Who knew what he could have done with it?"
Stoner said he was in Philadelphia Thursday night, watching as his former basketball coach, Jim Phelan, was inducted into the Philadelphia Sports Hall of Fame.
"That's where I was when David was killed," Stoner said. "He was just so happy and satisfied. His job reigned supreme in his life. I can't believe he's gone."
Stoner plans his own simple memorial on a tree stand - a hunting perch - in the fields they shared in the picturesque Carroll Valley, not far from the Maryland line.
"We're going to put up a plaque in his honor on one of our tree stands," he said. "It will soon be known as the David L. Grove Tree Stand."
Contact staff writer Amy Worden at 717-783-2584 or firstname.lastname@example.org.