From a high-rise rooftop on the west side of the Schuylkill, a 20-year-old Drexel University student allegedly operated a flying camera drone recklessly all the way to the Ben Franklin Bridge, and it nearly collided with a police helicopter Wednesday evening.

At one point, Joseph Roselli allegedly flew the drone as high as 1,500 feet, which is restricted for use by Philadelphia International Airport.

Roselli was charged with risking a catastrophe and recklessly endangering another person, court records show. He was released Thursday after his $3,700 bail was posted.

The Federal Aviation Administration said it was investigating the incident.

The helicopter was monitoring a protest against President-elect Trump at 18th and Walnut Streets around 6 p.m. when the drone suddenly appeared, forcing the police pilot to veer away to avoid a collision, said Chief Inspector Joseph Sullivan.

The drone also flew in from the side and "at the last minute goes underneath the helicopter," Sullivan said. "We could've had a true catastrophe."

A 6ABC news helicopter also watching the protest followed the drone to the roof of a high-rise in the 2900 block of Chestnut Street and recorded video of Roselli operating the drone remotely, Sullivan said.

Police went to Roselli's student residence at evo Philly at Cira Centre South, recovered the drone, a DJI Phantom 4 Quadcopter, and arrested him.

The Phantom 4, which has a listed retail price of $1,200, is 8.8 pounds and measures 15 inches across.

Sullivan, who oversees homeland security for the police, said he believed Roselli was flying the drone to collect footage throughout Center City and did not have a particular interest in the protest.

Roselli could not be reached for comment Thursday.

FAA guidelines for recreational use of an "unmanned aircraft system" state that a drone should always be flown within the operator's sight, should not be flown above 400 feet, and should never be flown over groups of people. Though those are guidelines, they will be factored into any decision to file federal charges against Roselli, Sullivan said.

bmoran@phillynews.com215-854-5983@RobertMoran215