NEW YORK ( CNN ) -- With the weekend arriving and a long day finally over , 8-year-old Cherrie Mahan stepped off her yellow school bus on a chilly Friday around 4 p.m. Cherrie Mahan 's third-grade school photo was used on her missing child flyers . The bus stop was about 100 yards from her home in rural Winfield Township in western Pennsylvania . But Cherrie did not make it to the hilltop trailer she lived in with her parents . She was never seen again . Investigators say her disappearance after the four mile ride home from elementary school on February 22 , 1985 , remains a mystery . `` It 's like a black hole opened up and she fell in , '' said Cherrie 's mother , Janice McKinney . She recalled that she and Cherrie 's stepfather , Leroy , could hear the bus pulling up that day . Soon after Cherrie did not arrive , he went to the stop to look for her . ''He came flying back up because she was n't there , '' McKinney said . Watch what the girl 's mom has to say » . Cherrie , an only child , would soon be celebrating her 33rd birthday , but in the minds of many , she will always remain a missing girl . `` People still talk about it , '' said Trooper Frank Jendesky , the lead detective working on the case for the Pennsylvania State Police for the past 15 years . The driver and children riding the bus remember Cherrie getting off the bus with a few other students who lived nearby . One lingering detail has baffled investigators for years -- reports that a 1976 model van was following the school bus . The van , according to students , had a distinctive painted mural of a snow-capped mountain and skier wearing red and yellow clothes coming down the mountain . Despite many efforts , the van was never found and it remains unclear whether it holds a link to the puzzle . ''By now it 's probably in a junkyard or somewhere , '' said Jendesky , who considers the case a kidnapping or abduction -- rather than a homicide -- because a body was not found . `` It 's the not knowing that kills you , '' McKinney said . ''Every day you wonder and you look at some girl who 's 33 and you wonder , 'Is that her ? ' I look at little kids and wonder , 'Is that my grandchild ? ' '' Over the years , police conducted hundreds of interviews and cleared several persons of interest , while the case file grew to more than 4,000 pages . Among his biggest frustrations , Jendesky said : `` The time lapse and a lot of the calls I 've gotten over the years really had no relevance to the case . '' In the days before Amber Alerts and greater public awareness of crimes against children , McKinney said it took time before word of her daughter 's disappearance became widespread . McKinney said Cherrie 's case was included as a public service insert in a direct mail advertising campaign , one of the first times that approach was taken . Cherrie was especially close with McKinney 's parents . She described how the girl would lovingly mimic her grandfather 's daily morning walk in the garden with his hands cupped behind his back . Hanging in McKinney 's dining room is a picture Cherrie drew of a rainbow , trees , birds and clouds . It says `` Mom and Dad . '' `` I have more memories of my daughter than most people get in a lifetime , '' McKinney said , remembering that Cherrie loved the children 's character Strawberry Shortcake , enjoyed spelling and wanted to be an elementary schoolteacher . The day Cherrie went missing she was bringing home annual school pictures . That photo and the girl who never made it home with it became known to many on missing posters distributed across the nation . `` She was one heck of a special kid , '' McKinney said . `` And there 's somebody out there that knows . And I hope that someday they have a conscience and they 'll let us know . Because that 's all I pray for , is to have an answer . '' Anyone with information on the whereabouts of Cherrie Mahan or those responsible for her disappearance are asked to call the Pennsylvania State Police at ( 724 ) 284-8100 .
Third-grader disappeared in February 1985 . Police looked for , but never found van with mural of skier . Cherrie Mahan 's missing person flyer was one of first sent by direct mail . Know something ? Call the Pennsylvania State Police at ( 724 ) 284-8100 .