By design, spyware and stalkerware are hard to detect and can be just as hard to remove. It is not impossible in most cases, but it may take some drastic steps on your part. Sometimes the only option may be to abandon your device. . When removed, especially in the case of stalkerware, some operators will receive an alert warning them that the victim’s device has been cleaned up.
Link: How to find and remove spyware from your phone
via http://www.zdnet.com