Updated

Peruvian officials say more than 400 dead dolphins were found last month on the Pacific Ocean beaches where twice that amount were encountered in 2012.

Authorities never established the cause of death in 2012. They are doing autopsies now on the dolphins found in January in the Lambayeque region on the northern coast.

Technician Jaime de la Cruz of Peru's IMARPE marine life agency says about 220 dead dolphins were found the last week of January, the rest during the previous three weeks.

De la Cruz says autopsy results are expected in two weeks. Exams will focus on lungs, kidneys and livers.

Autopsies of some of the more than 870 dolphins found in 2012 were inconclusive. Speculation ranged from biotoxins in the sea to seismic testing to an unknown ailment.