WATERVILLE — At least two Colby College students will be charged with arson in connection with an on-campus dumpster fire Sunday morning that occurred a few hours after a bonfire at which a large crowd of students threw items at police and firefighters who arrived to put it out.

Student Jonathan Sdao, 24, of Niwot, Colorado, was charged with two counts of assault and refusing to submit to arrest after he allegedly threw a bottle that hit two police officers during the bonfire melee.

The bonfire occurred around 1 a.m. on a sidewalk at the senior dormitory off Washington Street and about 200 to 250 students were on the scene — a crowd so aggressive that firefighters didn’t want to get near the fire until police arrived, according to police Chief Joseph Massey on Monday.

Sdao is a member of the Class of 2016, but did not graduate Sunday, according to Ruth Jackson, vice president of communications at Colby.

The officers and a firefighter who were struck with thrown objects were not injured, but a student was struck in the head and taken by ambulance to the hospital, Massey said.

Colby will “conduct an investigation into the reported actions of the students,” Jackson said in an email Monday. She said the injured student was taken, evaluated and released from the hospital.

Sgt. Ken Grimes of the state fire marshal’s office said Monday that investigators have identified at least two students responsible for the dumpster fire, which was reported at 4:30 a.m. Sunday.

The students, who are from out of state, are expected to be charged in the next few days, after state fire officials confer with the Kennebec County District Attorney’s Office, Grimes said.

Arson is a Class A felony punishable by up to 30 years in prison — though a dumpster fire would not likely result in a sentence of that many years, he said.

Jackson said in her email, “We believe strongly in the need for everyone in our community to show respect for our first responders. Whenever necessary, we take appropriate disciplinary action.”

FIREFIGHTERS UNDER ATTACK

Firefighters early Sunday — just hours before Colby’s graduation — were called to the bonfire at the senior dorm, which has vehicle access off Washington Street rather than through campus, but is a short walk from other dormitories at the top of campus.

Massey said Colby College Security requested help at the scene, where students were burning mattresses at the bonfire, as well as furniture and other items.

The bonfire was large, Massey said, with flames estimated at 15 to 20 feet high.

He said many in the large crowd of students were drinking, and the fire department didn’t want to try to approach the fire without police presence “because they felt confronted.”

Mattresses and similar items are hazardous because of materials contained in them, he said.

Officers tried to get the students to leave the scene, but they became unruly and aggressive and did not want to back away, Massey said. They started throwing items, including beer bottles and cans and a bottle of wine.

“They also were shooting fireworks over the fire department and officers as they tried to put the fire out and at one point firefighters felt threatened enough that they actually sprayed water at students so they would back off so they could get to the fire and put it out.”

Massey said Sdao approached police officers Scott Dumas and Ryan Dinsmore, who became aggressive, got close to officers’ faces and was hollering at them, saying the officers were on private property. They determined Sdao was intoxicated, and at one point they moved him along, but Sdao shouted obscenities, turned around and threw a bottle that struck both officers, Massey said.

Sdao was arrested and taken to the police department, where he was released on $300 cash bail. Sdao is scheduled to appear July 19 in Waterville District Court.

Fire officials put the fire out after about an hour and a half, but returned at 4:30 a.m. for the dumpster fire.

Capt. John Gromek said Monday about 13 Waterville firefighters responded to the scene of the bonfire and another nine to the dumpster fire, where they cleared the scene sometime after 6 a.m. Gromek was not at the scene, but said reports from Sunday showed about $250 worth of furniture was burned in the bonfire and about $500 worth of pavement was destroyed, according to the report. Capt. Shawn Esler , who was at the scene, was not in the office on Monday to comment.

FIRE MARSHAL CALLED

The fire department called in the state fire marshal’s office about the dumpster fire. The items burned in the dumpster also included discarded mattresses, chairs and other items, according to the fire department report. Colby places extra dumpsters out for seniors to place items in that they do not want at the end of the year.

“We’re investigating the dumpster fire as an arson,” Grimes said in a telephone interview Monday afternoon. “We have identified some individuals responsible for it, and we have not revealed their names yet because no one’s been charged. We’re going to be conferring with the (district attorney’s) office on how to proceed.”

Grimes said investigators are processing paperwork on the case, and he expects it will be submitted to the district attorney’s office by Thursday. He said that because those responsible have been identified, his office does not think the public safety is at risk of another fire.

He said a decision about whether to arrest those responsible, or summons them, had not yet been made.

Meanwhile, Massey said the fires tied up a lot of resources — both police and firefighters — and police had asked law enforcement officials from other agencies to be on standby for Waterville.

If there had been another structure fire or an accident while officials were at Colby, police and firefighters would have been hard-pressed to respond to everything, he said.

Police have worked with both Colby and Thomas colleges to help educate students and spread awareness about underage drinking and what happens when a lot of people congregate and drink.

“Each year we work with Colby to try to minimize any problems, and I think, really, this year was a pretty good year,” Massey said. “It’s unfortunate it ended with this particular incident, but when these things happen, we’re going to respond and hold those people who are responsible accountable for their actions.”