Tom Shaunessy was an incidental character who appeared in Omnivore.
Very little is revealed about Shaunessy's early life. What is known is that he was one of the senior investigators hunting the Boston Reaper, a prolific serial killer active in Boston between 1995 and 1998. Despite the fact that he was never caught, Shaunessy still earned several awards during his time in the Boston PD, among them a Service Award presented in 1996 and an Outstanding Service Award. In 1998, he called Aaron Hotchner and the BAU for assistance. Shortly after that, when the Reaper had killed a total of twenty people and become unable to derive as much pleasure from it, Shaunessy received a letter with a contract from him, stating "If you stop hunting me, I'll stop hunting them. For as long as we both shall live, till death do us part." and the instruction to place the answer among the classified ads in the Michigan Post. Since the authorities had no solid leads and there was the threat of more victims, Shaunessy felt like he had no choice but to accept and shut down the investigation. Both of them honored the agreement, although he waited six weeks before he sent Hotch back, should the Reaper break his end of the deal. Over the following decade, Shaunessy continued working for the Boston PD before apparently retiring due to an unspecified illness requiring an oxygen tank.
Shortly before his death, he calls Hotch to him and reveals the deal, which is about to expire. Shaunessy then dies the next morning and the Reaper started killing again. He was then mentioned in Nameless, Faceless and 100.
- In the Season Seven episode True Genius, there is a minor character named Detective Bob Zablonsky, who shares remarkable similarities to Shaunessy:
- Both once worked as well-known police detectives.
- Both were heavily involved in the investigation of infamous serial killers (Shaunessy investigated the Reaper, while Zablonsky investigated real-life serial killer the Zodiac Killer).
- To add to this similarity, the Zodiac Killer was the primary basis of inspiration for the Reaper.
- Both became personally involved with the case, to the point where it was almost obsessive.
- Both retired from their careers from illnesses that left them bedridden.