The Royal Thai Police (RTP) will now look into five major biker gangs based in the country after arresting the leader and some members of the Outlaws Motorcycle Club in Pattaya on July 21.

The arrest of gang leader, an Austrian national "Mr Thomas", follows an incident in which a gang member, Olaf Thorsten Brinkmann, was involved in the murder of Hans Peter Walter Mack, 62, a German property broker in Pattaya in June.

Pol Gen Surachate Hakparn, deputy national police chief, told the Bangkok Post that police are still working to eradicate crimes conducted by foreigners living inThailand.

"Five major gangs are on our radar," he said, adding they are the Outlaws Motorcycle Club or Outlaws MC, Hells Angels Motorcycle Club or Hells Angels, the Bandidos Motorcycle Club, which is also known as the Bandido Nation, the Mongols Motorcycle Club or the Mongol Brotherhood, and the Vagos Motorcycle Club, which is also known as the Green Nation.

The Outlaws also have their networks in Phuket and Koh Samui in Surat Thani, he said, adding the other gangs live in other parts of the country, mainly tourist destinations.

The gang members tend to ride big bikes like Harley-Davidson motorcycles, have tattoos and are involved in narcotics distribution and other criminal activities including assault, extortion, theft, loan-sharking, fraud, money laundering, attempted murder or murder.

Most of the gangs in Thailand are run by Australian nationals, he said, adding they are international outlaw motorcycle clubs that have members in many countries around the world.

Their targets are foreigners. They demand protection fees from foreigners who want to run businesses in cities where the gang exists or even abduct them for money.

Pol Gen Surachate said the lack of strict law enforcement and corrupt officials are other reasons the gang members chose to base themselves in Thailand.

Some even get help from visa agencies or IB officers, such as the case in which 107 immigration officers helped more than 3,000 Chinese nationals involved in "grey" businesses obtain visas in February, he said.

"We will eradicate bad guys not only among gangs but also among police officials and agencies involved with foreigners. We need to make our foreign visitors feel safe when they come to Thailand," he said.