A man and woman were found dead Monday afternoon in an apartment in Sheepshead Bay, Brooklyn.
The investigation began last Friday when police said a man walked into a police station with a container that tested positive for cyanide.
Authorities said Erlendy Flores died after Flavio Godoy stuck a syringe filled with cyanide in her arm while she was packing clothes. Police said Godoy then drank cyanide himself and died.
Officials say the 51-year-old owner of a Port Washington jewelry store called for an ambulance after falling ill at the Manorhaven Boulevard shop Tuesday morning.