"Defense attorney Joshua Insley still believes that police used a stingray to find Taylor. He cited a letter in which prosecutors said they were prohibited by the Department of Justice from disclosing information about methods used in their investigation.

The portable device was developed for the military to help zero in on cellphones. It mimics a cellphone tower to force nearby phones to connect to it.

Records shows that the Baltimore Police Department purchased a stingray for $133,000 in 2009."

It is quite likely that there are passive devices that monitor cell phone channels without tricking them into connecting to a phony base station. These technically wouldn't be "stingrays". That is basically what the SIGINT satellites do. It could certainly be miniaturized for local area monitoring. In any case, the cell providers have basic details of what phones communicate with their towers. It doesn't seem like that avenue wasn't used in this case though.

I think it's more probable that they're covering their corporate friends, who have agreed to supply consumer data illegally. Were they using a stingray, they probably would have said as much.

Sure, if you take the word of the detective possibly covering up illegal actions.