This one took a slightly smelly detour . . .
I read and enjoyed your letter. Then, when I wasn’t looking, my wife threw the envelope in the trash.
Don’t blame her, she’s a neat freak. Always tidying up. But I was like, “Honey, dearest, where’s the envelope that came with this letter? I need that return address.”
Anyway, long story short, I rolled up my sleeves and fished it out of the garbage can. Pretty much disgusting, if you ask me. But you’re letter was worthy of a reply.
You wrote a thoughtful review of The Case of the Runaway Dog. Excellent and observant! I’m glad you liked it.
To answer your question: Yes! There is a new Jigsaw Jones book coming out this August, The Case from Outer Space. And by November, there will be 8 “classroom classics” newly available –- revised and updated.
You suggested a story where two detectives verse each other to see who can solve the case first. Well, I think I wrote one similar to your idea, titled The Case of the Double Trouble Detectives. In that story, rich-kid Reginald Pinkerton Armitage starts a rival detective agency. But as Jigsaw says to him, “Sure, you’re as rough as a pussycat. Why in the world do you want to get mixed up in this racket?”
Good luck tracking it down! It’s been out of print for a few years. Maybe you can find it in your library or on eBay. But never fear, there’s lots more Jigsaw Jones coming out soon!