Three Thursdays ago, Denis Reyes told his mother he did not feel well. He had been dealing with depression, a symptom of his bipolar disorder. He had recently been diagnosed with schizophrenia, according to his family, and he was very anxious about his health. His mother, Blanca Sierra, suggested he go see a doctor.

That evening, a crash in the bathroom jolted her and her other adult son, who also lives in their cramped three-bedroom apartment, decorated with crosses and pendants of the Virgin Mary, in the predominantly Puerto Rican section of the Bronx.

Reyes, 40, had pulled down the shower curtain and flung a bucket. In the kitchen, he threw a pot and tried to tear off the oven door. He stormed into the family living room, grabbed a lamp and threw it.

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"He lost his mind," Sierra told the Guardian in an interview at her home. "A person like this doesn't know what they are doing."

Sierra had grown used to her son's tantrums – even violence – but this was different. Reaching for her phone, she called 911.

Frantic, Sierra explained to the receiver that she needed an ambulance. Her son was having an episode and needed medical attention, she recalled telling the operator, who spoke in English. Sierra, who can not speak English, said she was transferred to someone who spoke Spanish, but this operator still struggled to understand her. She hung up the phone, praying help would come quickly.

An ambulance did come, eventually. But officers from the New York police department came first. An hour later, Reyes was pronounced dead at nearby St Barnabas hospital.