THANE: A 23-year-old Mumbaikar with a penchant for fast cars and dollars may have scripted India's biggest tele fraud. Shahgar Thakkar , or Shaggy , made nearly Rs 500 crore in one year by duping Americans till his game was busted by a disgruntled employee.Thakkar, who is on the run, ran three call centres that were collectively pocketing around Rs 1 to 1.5 crore daily by posing as US taxmen. The amount they stole from the innocent Americans is mind-boggling. In one case, one of the victims shelled out $60,000 just to escape a 'raid' on his house by taxmen, said police. Here's how he pulled off this sensational crime:1) Employees trained at illegal Mira Road call centres to use VoIP and placed calls to US citizens, handsets in US showed calls coming from +911.2) Caller identifies as employee of Internal Revenue Service, the American equivalent of I-T department.3) Using impeccable US accent, caller tells victim he/she has defaulted on taxes and must pay up immediately or else IRS would get him arrested4) Callers would first demand $10,000-20,000, later settle for $5,000-3,000. Victims told to make payment through pre-loaded cards1) Victims told to share 16-digit code of pre-loaded cash card with the call centre employee, who helped debit the decided amount.2) Though done through online payment mode, the amount debited by the victim in cash card would be redeemed.Some of the accused who helped Thakkar are based in US, they acquired the contact numbers from hackers and forwarded them to the Mira Road call centre. Data could cost about Rs 1 lakh for about 10,000 contracts1) Ads on social media and flyers invited candidates without any qualification for call centre work2) If a candidate shows potential, he is put through rigorous training in American accent.3) A six-page script is handed to them for mock calls. After perfecting the script, the candidate is inducted as employee.4) A small group of employees is picked for closing the calls, they are trained to issue threats and extort money from US citizensThe US gang members transfer 70% of the money they got through hawala channels. The employees were paid in cash. The US members kept 30% as commissionThakkar split his call centres into two floors. The top floor was for those making as low as $1.5 lakh per month. On the lowest floors would be those making $5-7 lakh per month.The "best performing" staffers were given reward of up to Rs one lakh. The employees were given liberal incentives for money they earned for the company by calling up US 'tax defaulters' and on several occasions upon seeing one employee getting big money others also followed the suit and won reward, police said.The racket was exposed after city police raided three call centres, which were run illegally at the premises of Hari Om IT Park, Universal Outsourcing Services and Oswal House in Mira Road.The police said though salary of the employees was in range of Rs 10,000-40,000 per month, some of them earned up to Rs 1 lakh per month.He stated that employees were fully trained in US accent and were given SOP and call sheet, based on which they used to make calls to the 'tax defaulters'.They use to make at least 100 calls per day of which 10 to 15 calls would materialise and of these three to four people would make payment under threat by the conmen.