Nearly a year after a teen stepped on an explosive device in Central Park that blew off part of his leg, the NYPD announced Wednesday it is raising the reward for anyone who can help them solve the mysterious case.

Police are hoping the now $40,000 prize will encourage anyone with information to come forward the mysterious case.

“Right now we are still missing a lot of answers and we need a lot of information,” Chief of Detectives Robert Boyce said during a press briefing regarding the perplexing case.

Connor Golden, 19, was “slack-lining” — walking on a rope strung between two objects — in the park with friends on July 3, 2016 when he jumped off some rocks and stepped on a plastic bag containing a homemade explosive device.

The device exploded, destroying his left leg below the knee.

The NYPD spent months running down leads, all of which have since been exhausted.

“We are attempting to ascertain who left this home made explosive device here” Boyce said.

“We’re trying to find out when [the device was placed] there. We think it was there over several days. We don’t know why at this point.”

Special Agent in Charge Ashan Benedict from the Bureau of Alcohol Tobacco and Firearms, which is also part of the investigation, said they need the public to come forward with photos and video from the area taken around the time of the incident.

“We’re calling on visitors to Central Park who may have taken photographs or video of the rock formation in the days and weeks before [the incident] to provide them to ATF and NYPD investigators to assist us in narrowing the timeline of when the explosive material was placed here as well as help us identify potential suspects,” he said.

Benedict said investigators have remained in close contact with Golden’s family, who earlier this month told The Post they are frustrated by the lack of progress with the case.

“Somebody knows something, has seen something,” Benedict said. “It’s a matter of them coming forward.”