Installation of Apps from Unknown source

[AC Question]

I use AUXUS NOTE 5.5. Recently i get installed with apps such as FILKART, HOLA LAUNCHER, OLA CABS, CLEAR TRIP, SWIFT WIFI etc., if i uninstall that app in Google Play Store its showing a notification "THE PARTICULAR APP IS NOT INSTALLED BY GOOGLE PLAY STORE. DO YOU WANT TO UNINSTALL ANYWAY?" I just dont know from where these apps are downloading from.....and my phone marks these as THREATS (App Market, Alarm Controller) and if i try to remove it says ANDROID CANT UNINSTALL IT...pls help me on this....

 

[AlphaTango414]

Welcome to Android Central.

My only suggestion I can think of is make sure to check Advice Administrators.
Last, a FDR might be in order.