There are some crime scenes detectives never forget.
For LIU Post criminal justice Professor Sean Grennan, hardened by years of investigating hundreds of homicides for the NYPD, it was that frigid February morning in 1980 when he arrived in an exclusive Queens neighborhood to find a successful Wall Street trader bludgeoned and fatally stabbed in his home.
He remembers every detail, every bloodstain -- even the bend in the knife because the killer had wielded the weapon with such force that the blade hit bone.
"I was in the house for 48 hours and it just stuck with me because it was a brutal, brutal homicide," Grennan said.
There was a frozen leg of lamb in the mudroom. Broken crystal was strewn about the living room, and the couch's brown upholstery was soaked with blood.
More than three decades later, a new twist in the case presented itself when the victim's grandson coincidentally turned up in Grennan's criminal justice class -- bringing new meaning to an event that had haunted them both.
It was on the first day of class on the Brookville campus this fall semester that they made the chilling discovery.
Massapequa resident Christopher Bates, 57, returning to college for the bachelor's degree he never got, was sitting in a second-row desk.
As Grennan introduced himself, speaking of his years working the Queens beat, Bates got the urge to interrupt.
"Maybe you worked on my grandfather's case," Bates blurted.
Grennan took one look at Bates. The family resemblance was undeniable. "George Robb," he exclaimed, as he pointed at Bates.
A few other students in the class gasped as Bates and Grennan, locked in a stare, recounted the details of a case that had gnawed at them both for decades.
"He mentioned Queens," Bates said. "And when he did I got a chill."
The slaying of his maternal grandfather changed Bates' family and the course of his life. He was 24 on Feb. 1, 1980, when he was summoned to his parents' home in Malba, an affluent waterfront Queens neighborhood.
He had grown up across the street from his grandfather's mansion, where he spent afternoons climbing maple trees in the backyard, listening to stories about the hustle and bustle of Wall Street in the 1930s.
His grandfather, George F. Robb, was 75 and retired as chairman of the specialist firm Robb, Peck, McCooey & Co., when he was stabbed to death by a random home invader, according to Grennan and police reports.
Bates was among those most affected.
"I just collapsed on the ground," Bates said, recalling the moment he was told what had happened. "He was my role model. To lose him just like that -- it was heartbreaking."
Robb had struggled with the killer, who eventually overcame him by striking Robb on the top of the head with a hammer, Grennan said.
His wife discovered his body that morning near the back door of the house.
The killing was covered on the pages of Newsday and the Daily News.
Grennan's investigation led to the June 2, 1980, arrest of Ronald Donaldson, of South Ozone Park, Queens, who was 16 at the time of the slaying. Donaldson pleaded guilty to manslaughter, robbery and burglary and served 26 years in state prison, according to state Department of Corrections records.
At the time of his grandfather's death, Bates was studying criminal justice at John Jay College. He left school, took over his grandfather's seat on the stock exchange and launched a successful career in finance.
But after his children were grown and he had retired in 2004, Bates decided to complete his degree. He set off on a second career in the law enforcement side of the stock market.
Bates said he never thought that in returning to college he would gain such emotional closure for himself and his family.
He was able to tell his mother, Dorothy (Robb) Bates, 83, about meeting Grennan before she died Oct. 29 at St. Francis Hospital.
"It is very fitting that after 32 years that I got the opportunity to thank him," he said.