Police in Essex are leading the investigations into offences of conspiracy to defraud and money laundering of more than £500,000.
Arrests were made off the back of hundreds of reports of people being scammed after buying tickets to sporting events.
Last year more than 500 victims paid for tickets for sporting events, but never received the tickets or a refund.
Six men, aged between 25 and 45, and two women, aged 25 and 35, all from Essex and London have been arrested and bailed until dates in April and May. Three other men have been interviewed voluntarily.
The investigation was launched after police were contacted by the National Fraud Intelligence Bureau (NFIB) regarding a company called Touchline Tickets. The NFIB analyses and assesses all reports made to Action Fraud.
The websites which currently form part of the investigation are:
Victims have reported losing more than £5.2 million to ticket fraud between Jan - Dec 2015. In June 2015 alone Action Fraud received 533 reports of ticket fraud, which included some of the websites under investigation.
With a number of large sporting events coming up this year, including the Rio 2016 Olympic Games and UEFA Euro 2016, police are urging people to only use official sources.
The investigation is continuing, however anyone with concerns who has not already contacted police can speak to Action Fraud on 0300 123 2040.