The Simple Way Apple and Google Let Domestic Abusers Stalk Victims
'Abusive phone-snooping, they point out, doesn't necessarily require software explicitly built for that purpose. Mainstream app stores are well-stocked with what those researchers call "dual-use" applications..'
If you have concerns about a victim of stalking here's some help I've collated. (I also deliver courses for front line professionals who support victims of cyberstalking)