Toronto police have arrested a man believed to be responsible for throwing feces at five people.

The man is accused of throwing a bucket of liquefied fecal matter at passersby in three separate incidents that took place between Friday afternoon and late Monday night in Toronto.

Samuel Opoku, 23, of Toronto, was arrested in the Queen Street West and Spadina Avenue area on Tuesday around 6 p.m. ET. Police would not say where exactly he was arrested.

Police said the man was charged with five counts of assault with a weapon and five counts of mischief interfering with property. He is due to appear in a downtown Toronto courtroom at 10 a.m. Wednesday. He is being held at Toronto police's 52 Division.

In a news release on Tuesday, police allege a man entered John P. Robarts Research Library, at 130 St. George Street, on the University of Toronto downtown campus on Friday and emptied a bucket of feces over a woman and a child seated at a table. The incident happened at about 5:20 p.m. ET.

Police also allege a man entered Scott Library, at 4700 Keele Street, at York University on Sunday and threw fecal matter onto a woman and a man. The incident happened at about 5 p.m.

Police further allege a man approached a woman in the area of College and McCaul streets on Monday and emptied a bucket of feces over her. The incident happened at 11:55 p.m.

A firefighter washes a sidewalk near College and McCaul streets after a bucket of feces was emptied over a woman on Monday. (Jeremy Cohn/CBC)

Const. Alex Li, spokesperson for the Toronto Police Service, acknowledged that the incidents were unusual for the city.

'It's disturbing. It definitely is. It's very disturbing. Let's just call it what it is," Li told CBC Toronto on Tuesday night. "We are definitely, as an organization, taking this very seriously."

Police released security camera images of a man on Monday and Tuesday, but it is not known whether the man pictured is the person who was arrested. Li said security camera images do help police find people responsible for criminal acts.

"I want to stress and thank the public for coming forward with information," Li said. "We've had calls. We've had information from the public with regards to these separate incidents."

Li said the investigation is still in its early stages even though an arrest has been made.

"This is definitely something that is very fresh," Li said. "Our officers are going to do their due diligence and our forensic officers are going to work tirelessly to obviously find out exactly what this substance is. There will be testing done."

Great work by <a href="https://twitter.com/TorontoPolice?ref_src=twsrc%5Etfw">@TorontoPolice</a> arresting an individual in the “feces attacks” investigation. He can’t face justice or be given help until apprehended and it seems our police have that in hand. I hope this arrest will help calm concern on campuses and across the city. <a href="https://t.co/AJ2kI6Y9Dt">https://t.co/AJ2kI6Y9Dt</a> —@JohnTory

Toronto Mayor John Tory expressed relief in a tweet at the arrest.

"Great work by Toronto Police arresting an individual in the 'feces attacks' investigation. He can't face justice or be given help until apprehended and it seems our police have that in hand," Tory said.

"I hope this arrest will help calm concern on campuses and across the city."

If there are any other victims, they are urged to call Toronto police, Li added. "There could be more charges laid if more victims come forward," he said.

Risk of infection from fecal matter is low, expert says

Earlier, in an interview with The Canadian Press, Dr. Isaac Bogoch, an infectious diseases specialist at Toronto General Hospital, said the public's understandable concern need not be complicated by concerns for their health.

He said that while fecal matter teems with bacteria, the human immune system is well-equipped to neutralize any contact with the substance — regardless of its source.

"Once in awhile a pathogen can slip past the goalie and cause an infection, but certainly if someone had an exposure like this the risk is still very, very low," he said.

Police said officers recovered the bucket used during the most recent incident and have turned it over to forensic investigators.