Bettien Martens ( Haarlem , 24 November 1951) was a Dutch criminal, better known as La Bella Bettien .

Martens was the daughter of an unmarried mother, which put her in a difficult position in the fifties. She followed the MULO , and appeared to excel especially in the field of language: she reportedly speaks eleven languages.

Martens ended up in the criminal circuit by wrong friends, and became an important drug link between Colombia and Europe. On September 24, 1992, she was arrested in a world-wide police action called Green Ice in Rome. The Italian Justice has offered her a witness protection program to obtain complete information about the criminal organization she has worked for in return for punishment reduction and long-term government protection against her former criminal relations. Martens has gone into this and has even testified against her Colombian bosses.

In the summer of 1994 she was released, and disappeared with a new identity and a different appearance. Her whereabouts have since been unknown.