How to stop Malicious location application?

Have her just take her phone to her phone carrier and have them find the program. Another possible way is reset her phone to factory setting. But make sure he isn’t using an app that is provided on her phone itself. In the mean time have her turn off location on her phone. I only turn my on when I’m using my phone as a GPS or if I’m doing a local search for a resturant near my location or searching for local radio stations when I play I heart radio on my phone. She may want to look at her facebook as well. If she has her facebook setting to update her location everytime she posts, she may very well be telling everyone on face book where she is. Google does the same thing I believe.
http://www.newmediarights.org/how_toconsumercreator/how_identify_and_remove_cell_phone_tracking_software

The simplest and hopefully only thing your friend might have to do, is turn off the GPS function on her phone, as @Pandora said.

These are great answers & there’s a bit more I’ll get to in a minute, but, does the device have to allow access?

I mean, the particular situation makes me feel unsafe as well & I need to know if he’s able to start tracking me or if he needs access to my device before he starts.

Is she driving a car? There are many models of trackers that can be hidden somewhere on or in the vehicle. They are not expensive and are difficult to find. Some only transmit once per day for a few seconds. :-(

Most likely it is a surreptitious phone app or she is allowing facebook or some other app to post her location. Did she ever allow him access? If her phone is older it might be time to ditch it an get another. That way she is reasonably sure of a clean slate as long as she does not fill the new phone with crap apps she does not need.

If she suspects he is watching and if she can stand being away from her phone for any length of time she could meet a friend or coworker for breakfast and hand it off. It would drive him crazy watching where he thinks she is going. If she can wait 48 hours she can even UPS it to herself: two airplane flights – to and from Kentucky!

Ooo… Here’s another one.
Did he give her a fitness band or watch as a gift?. is she wearing it?

My coworker had a tracking device that she put in her husbands car. It is about the size of a book of matches and about an inch thick. She always knows where he is. Your friend should search her car for such a device. It can be in the glove box, the crack of the back seat, or in the spare tire holder.

^ How wonderfully ethical.

Also, how can one sleep next to someone one trusts so little?

@Axemusica Do as I said above and make sure when you put your phone back on after the reset to include a strong password.
If you don’t want to do a reset, go over your apps for any that share information with people on your contact lists. An example of a simple one is Waze (a gps app). You can choose to share your location with someone on your contact list who has waze on their phone. So when you are driving it will contact that person and update them on your location. I never use that part of the app myself so I do not know if you have to give it permission to contact that person every time or if it just automatically runs everytime you put on Waze. My point is go through each app and read the fine print. If it requires gps and you don’t use it for driving or some app that is necessary to have it, then get rid of it.
Also if she has ever shared her facebook or email password , then she needs to go over her security information on both. For facebook, go to settings and then security. Then go to the section where it says where your logged in and recognized devices. If she ever set him up as a back up for her password retrieval than she should change it. She may have used his phone or computer at some point and never signed out. It would give him easy access to change her access settings. Instagram is also another tracking device. Everytime I see a friends post it usually tells me where the photo was taken and how long ago.

Don’t forget “Facebook find friends” !

It says right here.

https://play.google.com/store/apps/details?id=com.funreality.software.nativefindmyiphone.lite&hl=en

-To locate an iOS device, use iCloud credential that was used to activate the target device.

So the dude has her iCloud password and is basically using the find my phone function.

She clearly must change her password on iCloud.