Police tell the Wall Street Journal that the couple had argued on Sunday and the woman spent the night at her sister's apartment in the same Bronx building. The next day, police say, she returned to her apartment to collect her things while her brother waited outside for her.
Police say the husband, 41-year-old Flavio Godoy, stuck a syringe in Flores' buttocks while she was bent over packing her clothes. He then drank the same liquid from a cup.
The state Department of Environmental Protection will examine the liquid.
