A Florida mother credited her instincts for figuring out a man she spotted lurking behind a dumpster at her child’s elementary school was a registered sex offender.

The mother, who asked not to be identified, told FOX13 Tampa that she saw the man earlier this month walking alongside the building when she sensed something was off.

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“He stopped behind the dumpster out of my view. And he stayed behind the dumpster,” she told the station. “So I'm like, 'This is weird.'"

On a private Facebook group, parents had been posting about a “man on a bicycle” who frequently passed Bauder Elementary School in Seminole at dismissal time, the Tampa Bay Times reported, citing a formal complaint made to the Pinellas County Sheriff’s Office last year.

Another mother in the group had looked up an online list of the state’s registered sex offenders and identified the man they believed was prowling on the school’s grounds, FOX13 reported.

The mother said she knew to be on the lookout for a man with “long hair, riding a bike.” She said she followed her instincts and called the police.

Herbert John Saxton, 67, was arrested Friday on a charge of trespassing on school grounds, an arrest report said. He was later released on $1,000 bond and fitted with a GPS monitor, according to police records.

"There's no replacement for a mom's instinct.” — Mother speaking to FOX13 Tampa

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Saxton previously served four years of a 10-year sentence from 1997 to 2001 on sexual battery charges from an incident in 1988, according to state sex offender records. In 2004, he was charged with failing to comply with sex offender registration and was fined.

"There's no replacement for a mom's instinct,” the mother added. “And if it feels wrong, usually it probably is.”