On July 3rd, 2016, an explosion rang out in Central Park after an 18-year-old tourist named Connor Golden jumped from a rock near Fifth Avenue and 62th Street and landed on a homemade explosive device, which blew off his lower left leg. Three years later, and despite a $40,000 reward, the investigation into the bombing remains open, frustrating Golden's family.

"We want to have answers for Connor. And we also want to have answers for the family," Detective Andrew Cohen, who is heading the investigation for the NYPD, told NBC New York. "The homemade explosive that was utilized—the high explosive that was used—is very unstable and transporting it from far distances would be very risky. So we believe that it could be in this area—in the New Jersey and New York area."

Authorities believe that the person who left the device was testing out a homemade explosive, as traces of triacetone triperoxide, or TATP, were found. (TATP is what Richard Reid used in a shoe that he tried to light on fire on an American Airlines flight in 2001.) However, the device did not go off and the police believe the bomber left the "shock-sensitive" device by a rock formation in the park, only for Golden to set it off when he jumped from a rock while slack-lining with friends.

Last year, the NYPD and Bureau of Alcohol, Tobacco, and Firearms released an image of a bag from La Unica Bakery, which has locations in NJ, similar to the one found at the scene. The bag apparently contained the explosive, and police found pieces of it after the blast.

But Jason Li, La Unica's owner since 2010, said to NBC New York, "I’ve never used this bag since I took this business over."

Kevin Golden, Connor Golden's father, said, "It’s not like this is a bag coming from Target or Wal-Mart. We would implore people in New York to really cast back and give some thought to their connections to that bakery. People they know, people in their network that have frequented that bakery and maybe make some connections of any kind of suspicious circumstances."

The father told NBC New York that his son, now 22 and a senior at the University of Miami "has, in some ways, moved on more than we have. He has forgiven. I don’t know how he’s done that. But we haven’t. We're still very much focused on figuring out how this could have possibly happened."