NEW : `` More investigation needs to be done , '' says a marine biologist . Official : The dolphins were found over a 220-kilometer ( 137-mile ) area of coastal Peru this year . They are believed to have been born in the wild and then taken into captivity by fishermen who had caught them illegally. Speaking to CNN , he said he expects test results to be ready within the week . " Dozens of dolphins have also washed up in the United States and Brazil this year .
NEW : `` More investigation needs to be done , '' says a marine biologist . Official : The dolphins were found over a 220-kilometer ( 137-mile ) area of coastal Peru this year . They are believed to have been born in the wild and then taken into captivity by fishermen who had caught them illegally. " Dozens of dolphins have also washed up in the United States and Brazil this year .