A man who walked through the Bourke Street Mall with a semi-automatic handgun in the wake of the January killings there has been charged with more than 130 offences, as police continue to investigate the security companies that employed him as an armed guard.

Aaron Purvis was dressed in black tactical clothing and carrying a Glock handgun in the Mall on January 25 – five days after Dimitrious Gargasoulas allegedly ploughed a car into dozens of people in Melbourne's CBD, killing six and leaving 31 in hospital.

Police started an investigation into Mr Purvis after Fairfax Media photographed him in the Mall, including at a makeshift shrine to the victims.

He was seen with a Glock semi-automatic 9mm handgun and a spare magazine, and dressed in a black tactical vest, a black shirt, and dark cargo pants.