The Secret of the Caves
The Hardy Boys series is considered a mystery/adventure fiction series for young adults. The stories usually revolve around teenage detective brothers, Frank and Joe Hardy, as they solve various mysteries and crimes.
In the Hardy Boys series, created by Edward Stratemeyer, Frank and Joe Hardy do not die. They are fictional characters who star in a long-running series of mystery novels for young adults.
Henry Kurt is in book #33 (The Yellow Feather Mystery) in the Hardy Boys series
Yes. It is called The Mystery of Cabin Island.
The Nancy Drew series The Ghost of Mercy Manor Dial-A-Ghost The Hardy Boys series
The first Hardy Boys episode with Callie Shaw is "The Mystery of the Haunted House" in the second season of The Hardy Boys/Nancy Drew Mysteries aired in 1977. Callie Shaw is the girlfriend of Joe Hardy in the series.
According the the Hardy Boys Wiki she makes her 1st appearance on page 8 of Book #45 (the Mystery of the Spiral Bridge)
The second Hardy Boys mystery book is titled "The House on the Cliff."
Both series were created by the Stratemeyer Syndicate, a children's book packager which also created the the Bobbsey Twins, Rover Boys, and Tom Swift series. The printed authors for all of these series are pseudonyms (fake names used by many authors). There have been two ND/HB crossover series: The Nancy Drew and Hardy Boys SuperMystery series produced 36 books from 1988 to 1998, and the Nancy Drew and the Hardy Boys Super Mystery series, which has produced four books since 2007.
Try the Nancy Drew or Hardy Boys series. Also Judy Blume writes on that age level, I am not sure if she writes mystery.
In the Hardy Boys DVD series, Rick Nelson sings the song "My Rifle, My Pony, and Me" during the episode "The Mystery of the Hollywood Phantom." The song was originally performed by Rick Nelson in the movie "Rio Bravo."
Some popular children's mystery book series from the 90's were "The Boxcar Children" by Gertrude Chandler Warner, "Nancy Drew" by Carolyn Keene, and "The Hardy Boys" by Franklin W. Dixon.