Hallmark has quietly announced on social media that “Mystery 101” has been officially canceled. The news came during a marathon of “Mystery 101” that aired on Hallmark Movies & Mysteries on Sunday, April 23. Hallmark Wrote: ‘Our Talented Sleuths Have Solved the Last Mystery’On April 23, Hallmark shared a post on its official Hallmark Movies & Mysteries Facebook page about the “Mystery 101” marathon that was airing. Wish Hallmark would start again with another series.”The official Hallmark Movies & Mysteries account replied, writing: “We loved making “Mystery 101” and we’re so glad you enjoyed sleuthing along with us. You’ve decided to end your most successful mystery series, without resolution, a cliff hanger.