Dennis Lehane, the author of best sellers-turned-blockbusters "Mystic River" and "Gone Baby Gone," is calling on the public to help solve a real-life mystery and is promising to name a character in his next novel for the good Samaritan who cracks the case.

Lehane's beloved rescue dog, a black and tan Beagle named Tessa, went missing near his Brookline, Mass., home after jumping a fence on Christmas Day.

In an urgent appeal on Facebook that quickly went viral, Lehane pledged to name a character in his next book for anyone who could find the pooch.

"Naming of character in the next book for anyone who gets her back to us! (No, really!)," he posted to Facebook.

Lehane described the dog as "smart, fast, and immeasurably sweet. She doesn't have a mean bone in her body."

The dog was not wearing its tags, he wrote, but is implanted with a microchip that reveals her ownership when scanned by a device at veterinarians' offices.