Here are some of the most prominent cases.
Day, a 25-year-old graduate student from Illinois, was last seen in Bloomington on Aug. 24. His family in Danville and a faculty member at Illinois State University reported him missing after he did not show up for class for several days.
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As of Monday, a news release by the Bloomington Police Department confirmed officers are still investigating and seeking leads in regards to Day. A body found during the search for Day is waiting for identification from the Illinois State Police crime lab, according to Officer John Fermon.
Anyone with information about Day is asked to contact BPD Detective Paul Jones at 309-434-2548 or at Pjones@cityblm.org.
Holloway mysteriously vanished without a trace during a 2005 high school graduation trip to the paradise island of Aruba.
Her puzzling disappearance sparked a worldwide media frenzy and a massive search of the island. Though an Alabama judge declared her legally dead in 2012, Natalee's body was never found, and to this day, it is still a mystery what happened.
But one detail that has never swayed is the central suspect involved: Joran van der Sloot.
He and Holloway met at a hotel-casino that summer night, and witnesses say they saw the pair leave a nightclub together. But what transpired next has been in question ever since.
Holloway’s father and a private investigator recently sat down with Fox Nation host Nancy Grace.
"A Natalee Holloway Investigation with Nancy Grace" is available to stream now on Fox Nation.
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Lauren Spierer, right, a 20-year-old student at Indiana University, disappeared June 3, 2011. Police say Spierer was last seen walking alone and barefoot to her apartment complex in downtown Bloomington, Ind.
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Spierer, a 20-year-old Indiana University student, vanished after partying with friends. National media shined a spotlight on the case, but official and private searches turned up nothing.
Spierer was last seen walking to her apartment at 4:15 a.m. on June 3, 2011. Immediate search efforts were made all the more urgent by a heart condition that required Spierer to take daily medication.
Fox News has reached out to the Bloomington, Indiana, police department for any updates on the investigation now more than a decade old.
Her family still operates a Facebook page, with the last status update posted Aug. 7.
Dulce Maria Alavez
Dulce Maria Alavez, 5, vanished from Bridgeton City Park on Sept. 16, 2019.
Now 7 years old, Alavez has been missing for two years. According to her poster on the National Center for Missing and Exploited Children website, she was last seen on Sept. 16, 2019, at the Bridgeton City Park behind Bridgeton High School in New Jersey at approximately 4:20 p.m.
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When NCMEC was contacted regarding this story, a spokeswoman suggested the following children’s names to include to garner more attention in their searches: King Walker, Vanessa Morales and Ava Baldwin.
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Anyone with information regarding any of these cases is urged to contact law enforcement.
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