Episode One question

[riventhorn]

 Question about Episode One and why eating dried fish gives Lin Jing a clue.

We see Lin Jing in his lab looking at something under the microscope--presumably from the crime scene where Lu Ruomei died. When he eats the dried fish, he says "fish" and this apparently gives him the clue he is looking for. Da Qing later calls ZYL and tells him they have a lead, and they head to the abandoned building, presumably expecting to find the shadow-Dixingren there, where Lin Jing once again scrapes something from the wall. 

So--why does "fish" give Lin Jing the clue he needs? How do they know to go to the abandoned building? What am I missing? 

Comments

[riventhorn]

All I could think of was that Lin Jing is trying to use the trace evidence to pinpoint where the shadow figure is hiding (like in shows where they use the soil left in the culprit's footprints to id that he is hiding by the riverbank or something). And so maybe the abandoned building has something to do with fish? A storage facility or something?

But all that is a stretch. It could also be that some crucial linking scene or dialogue got cut.