This gang earned the "Pink Panther" nickname because they once hid a diamond ring in a jar of face cream — just like the crooks did in one of the Pink Panther movies. As The New Yorker has written about the modern-day gang:
"All told, the Panthers have performed hundreds of robberies all over the world. The gang's cinematic name is an invention of the press: the police, after raiding one thief's apartment, found a blue-diamond ring, worth seven hundred and fifty thousand dollars, hidden inside a jar of face cream; a similar hiding place was used in one of the Peter Sellers films."
Oh, and about that David Niven reference. Here's how IMDB.com begins its synopsis of the plot of 1963's The Pink Panther:
"As a child, Princess Dala receives a gift from her father, the Shah of Lugash: the Pink Panther, the largest diamond in the world. This huge pink gem has an unusual flaw: looking deeply into the stone, one perceives a tiny discoloration resembling a leaping pink panther hence the name. As the camera moves in, this image comes to life and participates in the credits. When Dala is a young woman, rebels seize power in Lugash and then demand possession of the jewel, but the exiled princess refuses to hand it over.
"Dala (Claudia Cardinale) relaxes on holiday at an exclusive skiing resort in Cortina d'Ampezzo, where noted British playboy Sir Charles Lytton (David Niven), who leads a secret life as a jewel thief called 'The Phantom,' has his eyes on the Pink Panther. His American playboy nephew, George (Robert Wagner), follows his uncle to the resort hoping to steal the jewel and blame it on the Phantom, not realizing that the Phantom is his uncle."
Peter Sellers, the original Inspector Clouseau in the movies, died in 1980. Herbert Lom, who played the exasperated police chief Dreyfus, died in 2012. The movies' director, Blake Edwards, died in 2010.