NYPD loaned their stingray to a Texas LE investigating another case that is on Websleuths (Missy Bevers) .
Stingrays used to be the wild Wild West.
On this case, it states in the affidavit that a search warrant was executed on a cellular device. Dependent on policy, governing laws etc. could have been used here, in theory.
With regards to how law enforcement learned of the suspect discussing this case; I sincerely doubt any of the aforementioned information gathering techniques were used. A CI? Maybe, but this guy deteriorated rather quickly, I believe. Thus, who would have time to flip on him? A significant other? Plausible. An individual wearing a wire? Plausible, although not nearly as common as many believe.
In all likelihood, the suspect was speaking freely about the case, I would opine. He asserts a level of arrogance, it appears to me. Moreover, I'd hypothesize the suspect is a control freak, having analyzed similar, unrelated cases. The suspect will not disclose where the victim is located, yet he knows. This allows him to continue as the center of attention, I believe.
Also, if the suspect does have a partner (have not seen a verified link that he is married), it wouldn't surprise me if he had engaged in domestic violence type behaviors; physical, verbal or both.
Just my thoughts. Sorry, got a little off track.
- Nick