As agents closed in on him in the woods of Southwest Miami-Dade, kidnapper Thomas Knight shot his two hostages execution-style, then buried himself in the mud atop $50,000 in stolen cash.

The savage 1974 murders of Bay Harbor Islands businessman Sydney Gans and his wife Lillian landed Knight on Death Row — but the legal case is still churning after nearly four decades.

The latest chapter: a Miami federal judge late last year tossed out Knight’s death sentence for the Gans murders. Prosecutors are now appealing the ruling.

Knight, 61, nevertheless remains on Death Row for a third murder: the fatal 1980 stabbing of corrections officer Richard Burke.

“It’s gotten to the point where it’s a slap in face,” said Judd Shapiro, 48, the Ganses’ grandson.

Said the Ganses’ daughter, Harriet Shapiro, now 72: “Even though I have no hatred in my heart and I don’t live with anger, I would be very happy to see him dead and stand there when they kill him.”

Only two prisoners have been on Florida’s Death Row longer than Knight. His murder of the Ganses, while unfamiliar to newer generations of South Floridians, was a major story in July 1974.

Sydney Gans, 64, owned a successful paper bag company and a minor league baseball team, the Miami Beach Flamingos. He taught his grandson to play baseball and served as a leader at his synagogue.

Gans also employed parolees looking for a second chance. Knight was one of them. He had worked for the paper company for 10 days when he kidnapped Sydney Gans at rifle point.

Knight forced him to drive to the Gans’ home, where he kidnapped Lillian Gans. The three drove to downtown Miami, where Knight forced Sydney Gans to enter a bank and withdraw $50,000.

Knight — armed with a semi-automatic .30-caliber carbine — held Lillian Gans in the back of the businessman’s car. Inside, Gans alerted the bank manager, who called authorities.

Gans, fearing for his wife’s safety, returned to the car. A slew of agents and cops covertly tailed the car as Knight ordered Gans to drive to West Miami-Dade.

In a blunder that still riles the Gans relatives today, agents lost track of the car. In a secluded wooded area at Southwest 132nd Street and 117th Avenue, Knight shot each of the Gans with a bullet to the neck. He disappeared as heavily armed officers swarmed the woods.

For hours, authorities scoured the woods. Teargas was deployed. A deputy found Knight buried in the mud, the money and the rifle underneath his body.

Not long after his arrest, Knight and a group of inmates escaped the Dade County Jail. He remained a fugitive for 101 days until agents burst in on him holed up in a New Smyrna Beach shack.

Judd Shapiro — 9 when his grandparents were killed — remembers that while Knight was on the lam, a teacher was assigned to guard him while at school.

“Every child at some point comes to the realization that the world is not necessarily a safe place, and for me it came at a young age and in an extreme fashion,” said Judd, now an English teacher.

A jury convicted Knight in 1975. A judge sent him to Death Row.

While there in October 1980, Knight thrust a sharpened spoon into the chest of corrections officer Burke, 48. The reason: the prison would not let Knight see his mother, who was making her first visit.