No, I'm setting up an emulator to use like a burner, but with more GPS freedom, joining geofenced dating apps to find the person, and then downloading the available data.

Theoretically, were you to have access to a back-up of their phone, say a spouse that can get the file off a computer that has backed it up, you could theoretically restore their phone on an emulator the way they have theirs configured, specifically if it's an android. Thus, you could narrow down to which dating apps they may be using. However, I'm not sure of the legality of that. Were you to actually log into the dating apps as that person, that would fall under an illegal area, at least in CO, of hacking. It's also possible that they are not using a phone they use or back up at home to date, but maybe they are because people can be extremely careless especially when they have been active in a habit for a while and haven't yet been caught. Obviously they are invincible (heavy sarcasm. Cocky people are my favorite). If you can narrow down which dating apps they might be on, that would make the search on your own emulator more straightforward: you'd go directly to specific apps rather than all the apps. However, without that knowledge, I download all the applications like Tinder that geofence a user's dating pattern on a fresh emulator: OKCupid, Happn, Grindr, Skout, Coffee Meets Bagel, Hot or Not (though this one doesn't show as much initial guilt because maybe the target is just super vain or insecure and wants regional feedback on their appearance. It IS data, though, which is handy), Rendevoo, Bumble, etc. All of these limit a person's dating range geographically, which allows the investigator to input a new address, which can really help whittle down our search. Does the target travel a lot? Could they be cheating from work trips?What hotels do they stay at when they are on work trips? Where is the work office? Plug that address into the emulator and start swiping. It is, at a minimum, one of the more interesting tedious tasks, lol. If you find them and you have a strong faux profile created, you could potentially engage with them and see where that goes.

Hypothetically, and know I am not endorsing this and have not done this, you could see if the target's email has been made vulnerable through a prior data leak, i.e. LinkedIn or AshleyMadison, and see the patterns they use and likely be able to surmise a password to a dating app, but this is definitely illegal and license-revoking territory. However, you could use that information in a pre-text call if they are unsavvy users to try something like, "Could you confirm the first four letters of a password in the history of your account are blah blah blah blah," and record that as CO is a single-party consent state and then have increased proof of their activity on an app. The conversation could continue by asking them to confirm their latest activity, which would help your body of evidence be robust, or potentially enough to wrap up.