An instructor at a maritime skills development center in Kenner fatally shot a facility manager there Friday afternoon and was quickly arrested, Kenner police said.

Anthony Tardo, 49, of Mandeville, died after being shot once in the left side of his chest while he was in his office at Houston Marine, Jefferson Parish Coroner Gerry Cvitanovich said.

Kenner police Lt. Brian McGregor identified Tardo’s suspected killer as John Spears, who turns 51 on Saturday.

McGregor said Spears, of Marrero, had worked at Houston Marine for one year, and other employees at the business said they were not aware of any conflict between him and Tardo.

As far as McGregor could tell Friday, Spears’ only prior brush with the law was a 2004 arrest for simple battery.

The shooting at Houston Marine, whose offices are in a strip mall in the 2500 block of Williams Boulevard, was reported about 3:30 p.m., McGregor said. Cvitanovich said there was “no commotion” before Spears walked into Tardo’s office and shot him.

About 10 employees were inside the business at the time. One who heard the gunshot approached Spears and asked whether the noise had come from a simulator machine, which offers safety training for workers at offshore oil rigs.

McGregor said a shell casing was still spinning on the ground when Spears replied, “No, (Tardo) is going to need some help.”

After that exchange, police said, Spears went outside, put his gun atop a dark-blue Chrysler 300 sedan and waited for officers to arrive and take him into custody. Police processing the scene later Friday were spotted collecting evidence — including a wallet — from atop the car.

McGregor said police had not yet determined a motive in the killing, which he called the first workplace shooting to occur in Kenner in his memory. Investigators were meeting with Spears on Friday evening, he said. He added that co-workers could think of no reason for the killing.

A LinkedIn profile under Tardo’s name indicated that he had worked for Houston Marine since 1997. The profile said he was approved by the U.S. Coast Guard to conduct maritime safety courses and was skilled in first aid, CPR and being a helicopter landing officer.

Reached by telephone Friday evening, a woman who used to work with Tardo described him as the father of triplets, one daughter and two sons. Karen Ronquille said the only thing that possibly rivaled Tardo’s love for them was his work at Houston Marine.

“Anthony did everything that had to be done for the company,” said Ronquille, who worked with Tardo for almost 10 years at Houston Marine. “But he was (also) there for those kids for everything — he was the super Mr. Mom.”

Ronquille said it shocked her to hear someone would slay such an easygoing man, one who used to joke that working around so many women at Houston Marine had made him too nice.

“He was laid-back,” Ronquille said of Tardo. “He would say, ‘Do what you’re supposed to do, and we’re all going to get along.’ ”

Bryan LeCompte, the CEO of Houston Maritime corporate owner Falck Safety Services, said the shooting was an “isolated incident.” LeCompte knew Tardo, and he appeared visibly shaken as he spoke about the employee’s death to reporters gathered at the scene.

Another man cradled his head in his hands and wept on the hood of his truck after the shooting.

“We lost a friend, a co-worker and a great father,” LeCompte said. “Please pray for us. Pray for us.”

He made the sign of the cross and walked away.