Story from a second hand book I am reading: Organ Hunters. The writer is Gordon Thomas.

Dr Gustav Romer, once the heated Stasi’s medical supremo and the world leading immunologist, has long been thought dead. But in a secret clinic on a remote island off the coast of Central America, his medical genius has found new and terrifying applications. His patients are the world criminal elite: Mafia bosses, Triad leaders, the new czars of the Russian criminal fraternity, the lord of the Japanese underworld.

For them, Romer provides organ transplants. And the organ themselves come from the bodies of victims especially killed for that purpose.

Only one man can stop the sinister trade in death – David Morton of Hammer Force, the police agency created by the United Natgions. But, and his shadowy employer, the woman known only as Madam, may prove to be Morton most dangerous opponent yet….