Peter Brown told the Daily News that his mother, Patricia, was supposed to be under constant watch.
He said Montefiore Medical Center informed him Friday that a surveillance camera caught her leaving. Police were notified.
He said he got another call five hours later after a paramedic found her.
Brown says his mother had bruises on her face and ribs.
Peter Brown said the hospital told him she looked like she had taken a fall but was otherwise fine.
The hospital declined to comment, citing patient privacy rules.
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