A spokesman for the security company that employed both the Florida nightclub gunman and an armoured car guard who killed three co−workers in Edmonton in 2012 is defending its hiring practices.

Communications director Katie McLeod of the Canadian arm of U.K.−based G4S says the global security company does as much as it can to investigate its employees before hiring them, but it can’t guarantee they won’t commit violent crimes.

She said it uses both government and its own checks to clear potential employees.

"In Canada, you must have your provincial security licence before you are even considered for employment and that follows all sorts of processes with the different provincial authorities," she said Monday.

"It varies from province to province."

Omar Mateen, a G4S employee in Orlando, Fla., has been identified as the gunman who killed 49 people and wounded more than 50 others in an attack early Sunday on a gay nightclub in the city.

In 2012 in Edmonton, an armed G4S guard killed three co−workers and wounded a fourth while they were servicing a University of Alberta campus ATM machine.

Travis Baumgartner pleaded guilty to one count of first−degree murder, two counts of second−degree murder and one count of attempted murder in the Edmonton slayings and was sentenced to life in prison with no parole eligibility for 40 years.

He fled the shootings with more than $300,000 before being apprehended in British Columbia at the Canada−U.S. border two days later.

McLeod said G4S has since sold its armoured car division, which required staff to be armed.

Shares in G4S fell on Monday after it emerged that Mateen worked for the firm. The company said Mateen was subject to a detailed screening and checks by U.S. law enforcement, which reported no findings to G4S.

The FBI has reported he was interviewed twice in 2013 after he made inflammatory comments to co−workers and, in 2014, he was found to have had ties to an American suicide bomber.

McLeod says that all G4S guards in Canada must take an approved course and a police check is undertaken. She said G4S also uses a third party to undertake a five−year history verification on all employees and contractors before hiring.

She added that while American G4S employees carry guns at times while working, that’s not true of the 9,000 Canadian employees.

"Our guards are not armed," she said.

G4S is active in some 100 countries and has 610,000 employees.

It came under fire during the 2012 London Olympics after failing to provide the number of security guards promised to protect the games. The British military had to be called in to fill the gap.

— With files from The Associated Press

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