I believe the s4 mystery Danvers and Navarro will solve is the murder of Annie K

The series is written by a woman. The point was made that murders of indigenous women often go unsolved.

Navarro was fixated on the idea that someone from the mine killed Annie K because of her activism. I wonder how much Navarro explored other possibilities. The vast majority of murdered women are killed by current or former partners. Others are most often killed by family members or friends.

I believe the actual case these detectives will solve is Annie K's murder. They need to start asking the right questions.

Annie K's friend Susan thought it was weird that Annie K wanted to keep her relationship with Clark secret.

There's a reason Annie K wanted to keep the relationship secret. IMO Annie K wanted to keep it secret either because (1) her family would not approve (that makes her brother and other family members suspects) or; (2) she was seeing someone else before or during the time she was seeing Clark. If that's the case and her killer was shown in episode 1, the pool of suspects is very large.

I believe someone planted the tongue at Tsalal and possibly planted Annie K's phone at the loveshack trailer.

I hope they find Clark alive and are able to question him. I doubt Clark killed Annie K but he may suspect somebody.

The scientists' deaths may just be a distraction from the real season 4 murder mystery.