Pretty sure this is Dark Encounter (2019).
I watched a bit of it (the ending, and some of the beginning), and it contains everything you described, including the reveal that the girl was murdered by her uncle (the town sheriff) and buried in the woods. I'm not sure if the alien is ever shown on-screen, but it did seem to be trying to communicate with the parents, and let them know what happened to their daughter, using imagery and visions rather than words.
Here are a couple of relevant excerpts from a review:
Written and directed by Carl Strathie (Solis), Dark Encounter is the story of a family in grief after the strange disappearance of their young eight year old daughter. We check in with them one year after their little girl vanished and witness unusual things beginning to happen, from unusual flashing lights in the woods and other obscure phenomenon. The now fractured and cracked family are soon left bewildered by it all, and what follows is an invasive series of events involving life from another world amidst a backdrop of family issues, a marriage falling apart and uncomfortable interactions between individuals with their own unique concerns and demons.
There are, on occasion, moments of corniness that feel a touch over-the-top but it’s not often. There is also some questionable dialogue (this specifically stood out to me with the Sheriff’s visit to the family home and the resulting questions he asked), but again, this is rare, and doesn’t effect the enjoyment of the film. Overall, I was really impressed with the actors, especially Grant Masters who plays Kenneth, the uncle to the missing daughter, Maisie, and towns sheriff. His tormented guilt-ridden characterisation is delivered with a real sense of humanity. Laura Fraser (The Missing) as Olivia, the mother of Maisie, delivers a subtle, portrayal of a woman in a haze, her shock regarding everything that has happened and is happening is shown in a way that isn’t too wild or unbelievable. Mel Raido (Legend), as Ray, the pissed-off and bitter father of Maisie, delivers a gritty and angry performance that creates tension between Ray and most of the other characters, from his younger Brother Billy (Sid Phoenix) and his teenage son Noah (Spike White). Really, though, there isn’t really a weak performance to be found here, with everyone delivering and pushing the film forward. The twists and turns aren’t so frequent that they lose you in the maze of them all, but happen enough to keep you interested and involved. It isn’t a film that shy’s away from taking you places that you don’t expect, and I liked that.