(ANSA) - Milan, July 17 - Six former employees of Italian Internet surveillance company HackingTeam are under investigation in relation to the July 6 cyber attack on the company, police said on Friday. The same group of former employees had already been placed under a parallel investigation in 2014 for alleged theft of the company's source code, and police said the two investigations will now be merged into one. Italian postal police, who handle computer hacking crimes, are conducting a probe of computer equipment at the company's headquarters, without blocking the company's day-to-day operations. Police will interview about 20 former HackingTeam employees and contractors in the next few days as part of the investigation. In the cyber attack on the company, hackers released internal documents, email correspondence and the underlying source code of HackingTeam software, which is used by governments worldwide for conducting surveillance.