A man arrested in the death of a Camden woman found hidden in a closet admitted that he sat on her chest and strangled her, prosecutors said today. The woman, Robin Mitchell, 39, was found dead on May 15 in an apartment in the 2300 block of Federal Street. Investigators arrested Fernando Chapo, 29, yesterday. He was arraigned in Superior Court in Camden today, and his bail was set at $600,000. Prosecutors said Chapo was an illegal immigrant from Mexico who used several aliases. When he was arrested, he had an identification under another name, said Assistant Camden County Prosecutor...