Watching YouTube in the dark while lying down

Very pissed with helper. Just set up new cctv after few months. Trusted helper a lot. She always managed to settle my youngest even when she was crying very badly. So I can attend to my older kids. Asked her a few times (before setting up new cctv) how she managed to do it. She always said Coz she carried her. Never ever mentioned about watching show. Tonight my youngest girl cried damn badly for mummy. Husband asked helper to let my lo sleep. My lo stopped crying almost immediately after she went in. Out of curiosity, I checked cctv to see how she did it. And to my surprise, she was showing my baby YouTube in the dark while lying down! Checked back cctv for the last few days and realized she’s doing that every time! Means she might have been doing it for months before my new cctv was set up! Damn pissed!!!