I don't think they do have enough, and they'd be hoping to be able to recover her body before he is arrested and clams up for good.
So the idea is that Borce is not speaking now, though maintaining the preposterous fiction that she just went for a walk. But what about the phone pings of his and her phones? So the police need a dead body to finalise their claim that he killed her, for without a dead body it is still technically possible she just got a fake passport and absconded (VR) or left Borce after Sarah's 21st (The Rickard). Jesus, this is stupid. If i were on a jury i'd convict on the strength of what we publicly know, for i wouldn't need a dead torso to dismiss the theory she ran away. The pings damn him (no pun intended). The only wiggle room is if VR was up there and received the torso in a boot-to-boot transfer and then dumped it somewhere else, like 400km away. But even that is immaterial to Borce being guilty of murder. That is only pertinent to accessory after the fact charges. This just puzzles me. We have Borce convicted in the court of public opinion via pings, though the cops are not arresting. Perplexing.