I Know What I Saw — Kathryn Croft

You witnessed a murder.
But no one believes you.

When Ria moves with her husband to Silverleaf Heights, a lavish gated community, she tries to settle in and recover from the accident that nearly took her life. On the surface, everything is perfect; the neighbours welcome her with open arms, even though she doesn't feel she belongs, and she is safe and secure with all the security cameras and the locked gate.

Or is she?

Late one night, Ria witnesses a woman being murdered in the garden next door. When the police go to investigate, they find the neighbours away and no sign of disturbance. But Ria knows what she saw, and is determined to find out who the woman was - even if no one else believes her.

Then an anonymous WhatsApp appears on her phone - a video of another woman being murdered. When she looks closely, she quickly realises the woman is her. The message disappears, as if it never existed, but the meaning is clear: stop looking for the dead woman, or you'll be next.