A 3-year-old boy reported missing by his mother Tuesday morning was found safe hours later with his babysitter who told San Diego police his mother had dropped him off.

The sitter called police around 2:45 p.m. when they saw that police were looking for the boy, according to SDPD Lt. Brent Williams.

Lt. Williams said the boy was dropped off there earlier in the day and the mother had forgotten. The sitter told police his mother dropped him off.

When the mother reported the boy missing at around 10 a.m., she told investigators she left the room to use the restroom and when she came back he was gone, SDPD said.

The sitter told police the child was dropped off earlier than that.

Williams couldn't explain the mother's lapse in memory.

"Those are questions that we're asking the mother now," he said.

An SDPD Sergent told NBC 7 the mother, Maria Flores, was evaluated by doctors at the Psychiatric Hospital of San Diego County.

Upon further investigation, it was learned that Flores provided police with false information about her son's whereabouts. She was arrested and booked into jail.

According to Maria Isabel, Flores' sister-in-law, Flores remembered taking her 14-year-old son and 6-year-old daughter to school Tuesday morning but didn't remember dropping off her 3-year-old son.

Isabel said Flores was in a car accident recently and is concerned her lapse in memory could be tied to the accident.

Williams said it is protocol for police to contact Child Protective Services (CPS) in any missing child case and said CPS would conduct its own investigation.

SDPD said the boy, and Flores' two other children, are with police while officers question Flores and the sitter.

SDPD did not say if or when the children would be returned to their mother.

A helicopter was flying over the Linda Vista area aiding in the search, and K-9 search and rescue teams arrived around 11:30 a.m. The dogs were given a few of the boy's belongings to get his scent.

At 1:40 p.m., police confirmed they were bringing in additional deputies from the San Diego County Sheriff's Department.

The search area was expanded to include a five-mile radius before the boy was found.

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