Good Neighbours (2011)

Neighbors Spencer and Louise have bonded over their fascination with a recent string of murders terrorizing their community. When a new tenant named Victor moves into the building, all three quickly hit it off. However, they soon discover each has his or her own dark secret. As the violence outside mounts, the city retreats indoors for safety. But the more time these three neighbors spend together in their apartment building, the clearer it becomes that what they once thought of as a safe haven is as dangerous as any outside terrors they could imagine.

Unfortunately the movie Good Neighbours is not yet available on HBO Max.