The number of tigers held in captivity is more than double the number left in the wild, a new report by a wildlife campaign group has highlighted, echoing the horrific stories portrayed in the Netflix documentary, Tiger King.

The report published on Tuesday, Europe's Second-Class Tigers, revealed that there are just 3,900 tigers left in the wild compared with 7,000 captive tigers in the United States and an estimated 1,600 in Europe.

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It also documents the abuse and exploitation of captive tigers in Europe and the US.

"The trade in captive tigers dead and alive is a very serious problem," Kieran Harkin, the head of Wildlife Animals in Trade at Four Paws International, the organisation that published the report, told Al Jazeera.

"Our investigations reveal how captive tigers in private ownership, zoos, circuses and self-proclaimed 'sanctuaries' in Europe, are traded, bred and exploited. They're used as playthings, for selfies and as circus performers.

"And when the animal becomes too big, they are worth more dead than alive. The trade in tigers and tiger parts for the production of 'traditional medicine' in countries like Vietnam and China is very lucrative."

In Europe, the Czech Republic tops the list for numbers of tigers in captivity with 180, followed by Germany (164) and the United Kingdom (123), where the private keeping of captive tigers is legal.

Four Paws' investigations discovered that a tiger captive-bred in Europe can attract up to $24,000 to export. It added that one kilogramme of tiger bones are worth nearly $2,000.

The report also documents the shadowy network of traders and breeders operating in Europe who trade in the open using social media and public websites.

It highlights European "Joe Exotics" (a main character in the Netflix series) who operate facilities in Spain, Germany, the Czech Republic, Slovakia, France and Malta.

"Not only do captive tigers stand no chance of being rehabilitated into the wild, their trade also fuels the poaching of the few remaining wild tigers in the world," Harkin said.

Wild tigers are listed as Appendix 1 animals under the Convention on International Trade in Endangered Species, which means international commercial trade is generally prohibited. But captive tigers come under Appendix 2, which means that commercial trade is legal and only loosely monitored.