The source of large blots of oil staining more than 130 beaches in northeastern
Brazil remained a mystery Tuesday despite President Jair Bolsonaro's assertions they came from outside the country and were possibly the work of criminals.
Tamar, a group dedicated to the protection of sea turtles, said the oil spill was "the worst environmental tragedy" it has encountered since its formation in 1980.
The patches of oil began appearing in early September and have now turned up along a 2,000 kilometer (1,200 mile) stretch of Atlantic coastline.