Police on Monday were trying to determine the makeup of the explosive material that severely injured a tourist from Virginia over the weekend in Central Park.

The material — found in a plastic bag with matches nearby — was thought to have been left by an “explosive hobbyist or an experimenter,” said Lt. Mark Torre, commanding officer of the bomb squad.

“There are people who are fascinated by this kind of thing,” Torre said. “The fascination grows around the Fourth of July for obvious reasons. I believe we have someone who made this material and then he wanted to test it.”

The explosion left 18-year-old Connor Golden, visiting from Fairfax, Virginia, with a severe injury to his left foot after he jumped off a rock in the park, police have said.

Golden was in the park with two friends at the time. He reportedly had to have his foot amputated.

Torre said investigators were waiting for the laboratory results to come back, which were expected on Wednesday. But he said “how it was placed and what we believe would have been used to set it off” do not indicate that the person who put the bag there wanted to harm someone.

“The scenario that’s speaking loudly to us is that we have somebody that made this material,” he said. “There’s a great deal of information available if you know where to look for it on how to use chemistry to really create explosive material.”