— The man accused of causing a small explosion on Thursday that started a fire at a popular tree on the campus of the University of North Carolina at Chapel Hill was taken to a local hospital for a mental evaluation, according to the Orange County District Attorney's Office.

One person was taken into custody Thursday afternoon after authorities said a small device detonated at the Davie Poplar tree, which was planted when UNC-CH was founded. Police later searched a vehicle in Carrboro they believe belonged to the suspect did not find anything dangerous.

The suspect was identified as 24-year-old Joshua Daniel Edwards, a former student at the university. No charges have been filed, according to UNC officials.

Video taken Thursday shows a UNC professor attempting to put out the fire at the base of a tree when an explosion causes a fireball to erupt around him.

"I heard a large boom and looked back to see a 20-foot tall ball of flames," said student Evan White.

White said the professor, identified later as Dan Reichart, was burned on his face and arms and his shirt partially melted. Students tried to help by tossing water on him.

Video footage shows Reichart sitting on the ground as first responders rushed over.

The fire had been put out by about 4:45 p.m., authorities said. Reichart was treated for non-life threatening injuries.

Reichart said he was walking across the McCorkle Place park when he saw the fire at the base of Davie Poplar tree. He said he didn't see who started the fire but thought he might be able to put it out.

"I was an Eagle scout as a kid, so I've had lots of experience with fires, and I didn't think this one was too big to kick out," Reichart said in a statement to WRAL News. "I tried but it grew very quickly, and then it exploded.

"I would never had approached it had I suspected there was a pipe bomb in there."

Reichart said he teaches an astronomy class this semester, and he hopes to be back in the classroom by next week.

Jasmin Lazore, one of Reichart's students, said she is not suprised at all that he jumped in to help.

"I go to his office for office hours sometimes for help, and from what I've experienced, he's someone that likes helping and making sure that everything is OK," Lazore said.

Reichart, like many other on campus, likely knew the tree was not just any tree.

"Legend has it that when the university was first founded, they planted the Davie Poplar and as long as that tree stood, the university woudl prosper," said Danica Dy, a student and tour guide.

UNC police called Carrboro police following the incident to tell them to be on the lookout for a suspicious vehicle. A bomb squad arrived at the scene at about 5 p.m. and began investigating a 2011 Honda Civic parked in a public lot on Weaver Street.

After accessing the car's trunk and thoroughly searching the vehicle, no explosives or incendiary devices were found, according to Capt. Chris Atack.

Roads in the area were closed for several hours Thursday evening and the area was evacuated as police investigated

As an added precaution, Orange County activated its alert system, warning people about the incident and encouraging them to avoid the area.

Carrboro police said any evidence found in the vehicle will be turned over to UNC campus police.

The Davie Poplar tree is located in McCorkle Place near the Old Well on the University of North Carolina at Chapel Hill campus. Arborists inspected the tree on Friday and said it will be OK.