A 10-year-old girl left her family's home on the 1300 block of Brenthaven Lane in Florissant at approximately 6 a.m. Monday and has not been seen since, prompting an urgent search by St. Louis County police. Chylie Windston was barefoot when she disappeared, and investigators say she is unfamiliar with the surrounding neighborhood.
The St. Louis County Police Department has asked the public for help locating the missing girl, according to First Alert 4. Chylie is described as 4 feet 9 inches tall and roughly 90 pounds, and she was last seen wearing a purple-and-gray plaid shirt with a white cardigan. Anyone with information is urged to call the St. Louis County Police Department at 636-529-8210 or dial 911.
Why Police Issued an Advisory Instead of an AMBER Alert
Because there is no confirmed evidence that Chylie was abducted, police issued an Endangered Person Advisory rather than an AMBER Alert. Missouri's AMBER Alert system requires confirmed evidence of an abduction and an imminent threat of severe harm or death, while an Endangered Person Advisory can be activated through Missouri State Highway Patrol Troop F Headquarters whenever a missing person is considered at risk due to age, health, environment, or other suspicious circumstances, per the Missouri State Highway Patrol's outlined criteria.
Advisory criteria specifically flag environmental danger — including a child missing without adequate clothing or footwear — as a factor that can justify swift activation when an abduction cannot be verified. That likely explains why investigators emphasized both Chylie's bare feet and her unfamiliarity with the area when describing the case. The advisory system relies on voluntary partnerships between police and broadcasters to push alerts rapidly across local media networks.
No Waiting Period Under Missouri Law
Missouri law does not allow any waiting period before police can begin actively searching for a missing child. Under state statute, agencies must immediately enter a missing child into Missouri's MULES database and the national NCIC system upon receiving a report, a provision meant to counter the common misconception that police must wait 24 hours before acting.
That immediate entry gives local departments fast access to state resources. The Missouri State Highway Patrol's Missing Persons Unit, created under state law in 1985, operates as a statewide clearinghouse that generates standardized posters and coordinates national database distribution on behalf of local agencies like St. Louis County police.
The Numbers Behind Missouri's Missing Children Cases
Chylie's case adds to a substantial statewide caseload. Missouri State Highway Patrol records show 3,772 missing juvenile reports were filed across the state in 2026, with 434 active juvenile cases still open as of late August. Within St. Louis County alone, 451 active missing person entries — spanning both adults and juveniles — remained on file with the state as of the same period.
The advisory system has a strong track record. According to the Missouri Department of Public Safety, nine AMBER Alert requests in 2025 that did not meet strict abduction criteria were instead approved as Endangered Person Advisories, and all 11 children involved in those cases were recovered safely. Historical data from the Missouri State Highway Patrol also shows that more than 85 percent of missing children reported in the state are eventually located and returned home safely, with stranger abductions representing only a small fraction of cases.
As of publication, Chylie Windston's direction of travel and current whereabouts remain unknown, leaving the case open and public tips considered essential to the ongoing search.
