A man in his 20s was killed after falling from the roof from a Waterloo apartment building Friday morning.

Emergency workers were called to the under-construction student apartment building, at the corner of King Street and Bricker Avenue, shortly before noon.

Witnesses tell CTV News a man who was working on the roof of the 12-storey building fell onto scaffolding several floors below.

“A gentleman was hit by a skid of bricks that was being craned over off the top floor and knocked off,” says Ken Hadley, who was working on a lower floor of the building.

The man, whose name has not been released, was employed by Central Construction and was doing masonry work on the edge of the roof.

Hadley says the man was relatively new to the field and was not properly tied off.

The investigation into the incident has been turned over from to the Ministry of Labour.

"We have received notification that a worker has died after falling from a roof in Waterloo," ministry spokesperson Matt Blajer said in an email.

A large crowd of students from nearby Wilfrid Laurier University and other onlookers watched as the man was pulled down from the building.

An Ornge air ambulance was called in and landed at the Laurier soccer field, but left the area after the extent of the man’s injuries became clear.

Officials say charges are pending, but not expected immediately as the Ministry of Labour has one year to investigate the incident.