Thieves have reportedly stolen more than one million rand (£70,000) in takings after a Justin Bieber concert at Johannesburg's Soccer City stadium. The gang, armed with ropes, hammers and chisels, broke into a strongroom, according to local media and police. Officials at the stadium, which hosted the 2010 World Cup final, only realised the cash was missing on Monday morning. The haul included takings from the Justin Bieber concert and a gig the previous evening by rockers Bon Jovi. "The money was taken from the building and they only realised today," said a police officer from Booysens police station in Soweto. "We don't know how many people were involved as we are still gathering evidence." It's thought the thieves may have taken several days to chisel their way through a thick wall at the FNB stadium outside Johannesburg. They then lowered themselves by rope into a room used to store cash and escaped undetected. South African police spokeswoman Katlego Mogale said: "The suspect had gained entry through the roof. "They broke the tile of the bathroom between last night (Sunday) after the concert and this morning." Justin Bieber's Believe tour, which began in the US last September and ends in Atlanta in August, has been controversial at times. It has seen his pet monkey quarantined in Germany, drugs found on his tour bus in Sweden and the 19-year-old was criticised for a note he wrote at the Anne Frank House in Amsterdam. He also collapsed on stage in London and had to apologise to fans after arriving late on stage days earlier.