When new Jets wide receiver Eric Decker was 16 years old, two of his friends were shot and killed at their Minnesota high school. Decker, still deeply affected by the killings, has openly shared his experiences with others who have experienced similar tragedies. During Super Bowl week, The Post’s Howie Kussoy profiled the Jets’ new $36 million man.

The quiet of small town Minnesota had been broken.

“Code Red! Code Red!” over and over, a 16-year-old Eric Decker heard. That vague, yet distinct alarm of panic blared through Rocori High School, as students and teachers and faculty scrambled and sprinted and screamed. There were sirens, and the unmistakable, unsettling sound of helicopters.

There’s no forgetting the moment — Decker in the cafeteria, David Sauer in biology class, James Herberg in the hallway — when the shots were fired.

On Sept. 24, 2003, 15-year-old John Jason McLaughlin walked into the gymnasium and killed senior Aaron Rollins and freshman Seth Bartell, before gym teacher Mark Johnson bravely approached the shooter with the gun pointed at him, raised his hand and shouted “No!” at McLaughlin, miraculously prompting him to drop the weapon and end the senseless slaughter.

Decker, who was friends with both victims, was with Seth’s brother Jesse when the shots rang out. Decker sprinted through the school and past the gymnasium, ending up in a dark library closet, where he stayed for roughly 45 minutes with other students, consumed by confusion and fear.

“For me, it’s taken years to get over, and even now I still have times where I either remember something or am in a certain situation and become a little scared because of that,” the Broncos wide receiver told The Post on Friday. “Friends, family, the community … that’s who I leaned on during that time. … We are such a small town, a town of 3,000 people, so it really brought everyone together … the camaraderie and that support system.”

Nothing seemed easy in the immediate aftermath, but Decker’s friends said knowing that no one was going through it alone made all the difference.

“At the time, we just handled it by sticking together, hanging out with our friends, and if we needed to talk about, we talked about it,” said Sauer, Decker’s high school quarterback, next-door neighbor and best friend growing up.

“It took time,” Herberg, Decker’s longtime friend and current teacher at Rocori, said with a deep breath and a long pause. “It never truly was the same, but I always tell people, I would never come back and live in a community if I didn’t think it was a great place to live in. We have a lot of pride, and I think we handled the situation the best that anyone could handle the situation.”

Decker had grown accustomed to the quiet, being raised in the small town of Cold Spring, Minn. — a town along a highway, in the shadow of St. Cloud and cloaked in the anonymity of flyover cities in the Midwest.

It is a conservative, rural town, where the farms outnumber traffic lights and fishing is favored at several of the state’s 10,000 or so lakes nearby. It is a place where everyone may not know everyone, but everyone knows someone who knows everyone.

“It’s a pretty tight-knit community, no question about it,” Herberg said. “People go out of their way to do things for each other and I think that makes it special and unique.”

Decker was the all-everything athlete and be-everyone person at Rocori High School. Popular, witty and funny, Decker is described with the likeability of Ferris Bueller and the looks of Don Draper.

His father Tom was a two-sport athlete at St. Cloud State. His sister Sarah ran track at Columbia, while Eric, the youngest child of a middle-class family, was a three-sport star — football, baseball and basketball — who dreamed of going to the University of Minnesota. Playing on Cold Spring’s small stage, U. of M. was the only scholarship offer he would receive, but those surrounding him knew what so many were missing.

“In 25 years coaching here, I’ve never seen anyone like him,” said Joel Baumgarten, the school’s athletic director and Decker’s former position coach. “He’s a fantastic person. He was a really good student, smart, funny, had a little bit of everything. He’s also very humble and very classy, and was really coachable. He’d learn things very quickly.”

His talent was great, his determination greater. The future was whatever he wanted it to be.

“He was just that much better than everyone else,” Sauer said. “He had incredible talent, but he was also one of the most competitive people on the planet. He worked harder and cared more than anyone else.”

Decker would become a Golden Gopher, where he would star in football and baseball. He was selected by the Twins in the 27th round of the 2009 MLB draft and by the Broncos in the third round of the 2010 NFL Draft, after posting the highest Wonderlic score of all prospects at the NFL combine.

After turning pro, Decker often returned to his hometown, running football camps, making donations to his old team and visiting his group of high school friends who have remained close to him. He also found time to produce back-to-back seasons with 1,000-plus yards and double-digit touchdowns with the Broncos.

At a recent friend’s wedding, Decker’s former baseball coach and social studies teacher, Gary Distel, caught up with his former pupil. Distel said it felt like he had unpaused one of the countless conversations had with a teenage Decker.

“He was not this guy that had 85 catches and 13 touchdowns for the Broncos the year before,” Distel said. “He was just Eric, and I don’t think he’s forgotten that. Sometimes people forget that, and he’s never forgotten where he came from.”

Every so often, far too often, Decker is forced to remember the scar that can never fade, reminded of his town’s tragedy every time another school suffers the same fate.

Before Decker and the Broncos arrived for the Super Bowl, the standout wideout was brought back to that day — the surrounding tears and shrieks, walking out of the school with his hands in the air, seeing snipers on top of buildings and the unforgettable, inexplicable, irreplaceable losses.

On Dec. 13, less than 15 miles from Sports Authority Field at Mile High and less than nine miles from Columbine High School in Colorado, student Claire Davis was shot and killed at Arapahoe High School by fellow student Karl Pierson, who then took his own life.

Decker — understanding far too well what few could, or should, ever have to ever understand — recorded a moving video message for the school’s students.

“With the experience that I’ve been through, the least I could do is share my experience and help with the grieving period and let [people] know that in time you’re going to heal [and] to be sensitive with everyone,” Decker said. “You are on a platform as an NFL football player. As a professional athlete, kids look up to you and communities look up to you, so the biggest thing is to give back while you do have time.

“I do believe in fate, and things happen for a reason, so to be physically where I’m at in Colorado is an opportunity for me to have that chance to speak to people who have been through similar experiences and hopefully comfort some that hear the message.”

That tragic day in 2003 put Cold Spring on the map, but the community’s strength is what defines them.

“Every time that day comes, we always take a few moments and talk about how far we’ve come since [the shooting], and I guess we just really understand not to take life for granted and enjoy every day,” Decker said.

Decker, who is remembered fondly with pictures inside the school, is the pride of a town that only has grown prouder and closer in the past decade, the receiver holding that distinction more securely than a Peyton Manning pass. He even has turned a large number of the purple-blooded residents bred on Vikings football toward the orange-infused passion of the Broncos, and the star who never forgot where it all began.

Next Sunday in frigid Cold Spring, Decker’s friends and family, and the kids that look up to him, will gather around the televisions of rural Minnesota, watching Decker in a Denver huddle in the cold of East Rutherford, watching the town’s biggest star on the country’s biggest stage, living out his unlikely dream.

“We’ll be wearing our Decker jerseys and hoping for the best,” Herberg said. “I was just talking to him the other day, and, wow, what an opportunity.

“I always knew he was gonna do something special. Always.”

Additional reporting by Mark Cannizzaro in Englewood, Colo.