There were at least two separate falling incidents in the crowd of a Phish concert at the Chase Center in San Francisco Sunday night, one of which was fatal.
A 47-year-old fan who traveled from Athens, New York, for the concert, Ryan Prosser, died after falling before 9 p.m. during the performances, according to KTVU. Though the investigation is ongoing, police said Tuesday, per the Associated Press, that they believe he "leapt from an elevated area of the arena."
Spokespersons for the San Francisco Police Department and the Chase Center did not immediately respond to PEOPLE's requests for comment.
A witness told KTVU: "We were a couple rows behind the first guy that jumped intentionally and we saw him right when he put his feet on the barrier, stood up and just leapt. He went out of view and I realized later that was a huge drop, maybe four stories or so."
Prosser's longtime friend Frank Bauer told the outlet, however, that he doesn't think he would have jumped. "He was like a brother to me," he said.
Later in the evening, around 9:45 p.m., there was another fall. This time, a concertgoer fell into the lap of another fan, both of whom suffered non-life-threatening injuries, KPIX reported.
Evan Reeves, 44, described to the outlet the moment the person suddenly fell onto him, breaking his leg: "It was a loud thud, then sharp pain in my left leg and a guy's head in my lap. I right away dragged myself a few feet away to get some distance so he could be treated. I knew immediately what had happened because as an usher in the music scene, I had already heard many stories of people falling from balconies over the years."
Reeves insisted that he stay to watch the rest of the Phish concert after being cleared by a medical professional on-location.
"My first thought, after hoping the guy's okay, was hoping I wouldn't have to miss the second set. With the on-site doctor's consent, I convinced them to wheel me back in for the last 40 minutes while I waited for my wife to pick me up to take me to an Oakland hospital," he told KPIX.
According to KTVU, the Chase Center offered its "heartfelt condolences" in a statement, adding that the facility is a "state-of-the-art arena that was built and is operated in accordance with all applicable safety requirements governing facilities of its kind."