The 49-year-old suspect was seized on Sunday in Rio de Janeiro. His full name and nationality were not released, but Dutch media reported he was the chief suspect in the case. Three other suspects arrested previously were still being held and questioned, police said. Two of them were caught in the Netherlands Antilles.
A police statement said more arrests were possible, the AP reports.
Claudia Melchers, 37, was abducted Sept. 12 from her Amsterdam home and released unharmed two days later. Her father, chemical manufacturer Hans Melchers, has offered a US$1 million (Ђ840,000) reward for information leading to the arrest of the abductors.
Police say no ransom was paid and it was unclear why the kidnappers, who had demanded a ransom of Ђ300 million ($360 million) in cocaine, released. A.M.
The Ukrainian army is pulling back its forces beyond Chasov Yar, where they regroup and retreat to bases in Kramatorsk