The area around the University of Toronto’s St. George campus has now been reopened to the public after a security scare shut down the neighbourhood for hours Monday.

Police declared the campus safe after a thorough search. They had received reports from several people about a man dressed suspiciously in the area.

One of the callers took a photo of the man. The photo shows him wearing all black with a black knapsack and a mask over his face.

The male is not seen with a gun in the photo but Toronto Police Chief Mark Saunders said other callers to police indicated he may be armed with a weapon.

A heavily-armed SWAT team descended on the downtown St. George campus at around 10 a.m. after they received the report about the masked man.

Several buildings at the University of Toronto were closed and students were placed under lockdown while police searched the campus for anything suspicious. A number of downtown hospitals also said they were going into lockdown as a precaution, but that people with confirmed appointments would still be allowed in.

The TTC said that trains are passing Museum station on the Yonge-University Line while police continue to investigate. The trains resumed service just after 3 p.m.

A witness who was on the scene told CP24 that he saw a man wearing a “full plaid scarf over his face, staring up into the trees. It was very strange.” The witness also said the man he saw was pacing back and forth.

The man was last seen walking north, according to the witness.

Police are trying to determine if the man described as wearing the plaid scarf is the same person who was reportedly carrying a gun.

Officials have not determined if the person seen with a gun was actually a police officer responding to the area.

Police are speaking to students and staff as they board shelter buses to take them out of the area.

Initially, Saunders said a man placed under arrest at the scene was not connected to the incident. Around 2:30 p.m., Toronto police Sgt. Sean Cassidy told reporters that someone was taken into police custody in relation to the suspicious person reports. That person has since been released without charges.

The roads around U of T campus have been reopened and Cassidy said the Emergency Task Force has completed their search in three buildings.

“It is safe now for the staff and students to return to the buildings,” Cassidy said. “Police are taking down the crime scene.”

Torontonians are on high alert after a mass shooting in Orlando Sunday.

Omar Mateen killed 49 people and injured more than 50 others at a popular gay nightclub in Orlando before he was killed by police.

In a phone call to 911, Mateen pledged allegiance to ISIS.