A death investigation is underway to determine how a Lane Tech student who had been reported missing at Lollapalooza Sunday afternoon ended up being struck and killed by a Metra train hours later in the Lincoln Park neighborhood.

Sincere Ash, 17, was found about 6:15 p.m. on the tracks of an overpass near the Clybourn Metra station located at 2001 North Ashland, police and Metra officials said.

Ash, who was headed into his senior year at Lane Tech, had last been seen two hours earlier, at 4:15 p.m., at Lollapalooza, according to a flyer that had been circulating on social media.

A missing person report had also been filed with Chicago police, a police spokesman confirmed. Metra is leading the investigation.

There was a delay in identifying Ash because there was no cellphone or ID found on his body, according to Metra spokeswoman Meg Reile.

“The circumstances are still under investigation. How and why he got there it’s all under investigation right now,” she said.

Investigators have been unable to find anyone who saw what happened to Ash, Reile said.

His body was seen on the tracks by passengers standing on the platform who then reported it to authorities.

Callie Boustany was one of the Ash’s last friends to see him. Boustany, a senior at Lane Tech, was in line at Lollapalooza with Ash and friends after gathering at a friend’s house before taking a CTA train to the festival on Sunday.

Ash had lost his phone the previous night and was without it, she said.

Boustany said that Ash was moving further away from the group of friends in line. She confirmed that Ash had been planning on sneaking into Lollapalooza and said the group received a call from a peer saying that Ash was seen detained by police at the festival.

“Once Lolla was over, we just hoped that he was on his way home, but we had no way of knowing,” Boustany said.

According to a law enforcement source, Ash tried to jump the gates into Lollapalooza twice, but was caught and turned away both times.

Private security stopped him the first time. Chicago police stopped him the second time, the source said. He was not cited or arrested. A Chicago police officer gave Ash, who didn’t have any money, a few dollars to help get home, the source said.

No Metra train operators reported a train striking anyone. If an operator had seen a train hit a person “the train would have stopped immediately,” Reile said.

Metra trains are each equipped with a camera positioned at the front of the train to look 150 feet down the track. Investigators are reviewing footage, Reile said.

But it’s possible the camera wouldn’t have captured what happened if Ash had contact with a train closer than 150 feet or if he was hit by the side of a train.

Reile said she doesn’t believe the platform at Clybourn is equipped with security cameras.

Cade Pinalto, a classmate and friend of Ash’s, told the Sun-Times via Facebook Messenger that Ash had an exuberant personality.

“Sincere was an incredibly kind friend. His love for others could not go unnoticed. He had a contagious smile and joy. Anyone who knew him would describe him as a light because his presence seemed to light up a room. Sincere was fun, outgoing, and free spirited. He was always picking people up emotionally. He loved and encouraged his classmates well…”

A tweet sent out early Tuesday by the Lane Tech Basketball team read: “Our thoughts and prayers go out to the friends and family of Lane Tech Sr. Sincere Ash who was involved in a tragic accident this past weekend. Stay strong, Lane community.”

Another friend, Amira Hardman, who graduated from Lane Tech last year, said Ash “was one of the brightest people walking the Lane Tech hallways.”

Hardman, also contacted via Facebook, went on: “In the Lane Tech halls he was a superstar. He knew everyone and was the kindest person you could meet…. Sincere talking away in the halls or dancing his heart out. He was always glowing. He was an important part of Lane’s community because of how unique he was…Sincere was all of his friends’ go- to-guy when we were feeling low. His spirit was so pure and lovely you couldn’t help but to feel better when in his presence….”

Representatives from Chicago Public Schools, Lollapalooza and Lane Tech did not immediately return messages seeking comment.