A missing Syosset woman categorized as “high-risk” and “vulnerable” by police was found dead in a local sump, Nassau police said Monday.

The body of Deborah O’Connor, 58, was discovered at 3 p.m. Sunday in a sump at the rear of a business on Jericho Turnpike by Burke Lane, police said.

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Homicide detectives are investigating, but said there does not appear to be any criminality at this time. O’Connor’s body was taken to the medical examiner’s office for further examination, police said.

O’Connor was last been seen at her residence at about 4 a.m. Thursday, and police issued an alert for her shortly after midnight Saturday.

Police said in an update just before 5:15 p.m. Monday that O’Connor had been located, but did not indicate she was dead.