John is certainly keeping his eyes peeled, and they narrow in suspicion as he sees the red clay stuck in the tires. Quickly, he has to decide: does he attempt to stop this guy now, alerting him to suspicion while there's nothing concrete, or let him go and try to find him later? There having been two murders decides him; let's not give time for a third.

He turns his body towards the car and waves broadly, preparing to accelerate while saying "Ho, sir, could I speak with you actually?" 

He stops the car, leaning out the window to talk.

"Yes? How can I help you?"

With practiced ease, John palms two mystic tracking devices (mostly spider silk by volume, sticky and gossamer enough to avoid casual notice) and sticks one to an unobtrusive nook of the car. 

"I wanted to check if our personnel have had a chance to interview you yet about the murder?"

As John speaks, he unobtrusively spools out a thread of silk to float on the breeze, aimed to tangle in his hair. 

The man blinks.

"Interview me about the murder? Whatever for? I just heard about it and came to offer Zoshter my condolences; I expect half the town will do the same as word gets about."

"Just the general principle of 'if we question enough people some useful information might fall out' is all, like if you noticed anybody acting suspiciously last night, coming or going at odd hours, we would appreciate hearing about that!" John answers with a casual air, like of course the driver isn't under suspicion for anything. 

"Oh, right, of course. But no — I didn't notice anything. I live down closer to the center of town, so I would hardly expect to."

He points back the way John just came.

"Although ..."

"Yes?"

"Well, I was closer to Jannami, but Zosher just seems ... no, they're probably just rattled by the whole thing. Yes, it's understandable for them to be a bit off this morning."

He shakes his head.

"Was there anything else?"

At this point, the easy assumption is this guy is the murderer and trying to frame Zoshter. He'll go ahead and bite, though:

"Of course Zoshter is rattled, but now you've gone and made me curious as to how they seemed. But otherwise no."

"Alright. Well, best of luck."

He un-leans, and gently navigates the car off down the road.

And now he can track both person and car, at least in a vague directional sense. He ambles up to the porch, seemingly paying no more attention to the car, waiting for the dispatch person.

A moment later Mediator Dhobrev walks over from next door with some papers tucked under their arm.

"Hello again, Johntaylor," they say. Dhobrev is a face-recognizer, but even if they weren't, Johntaylor's unusual clothing would make it easy to remember him. "Angelad said you wanted to sit in while I ask some follow up questions of Zoshter; I'll ask them if they're comfortable with that, and then bring you in if so."

They step through the door, and a few short moments later beckon John into the house.

Inside, Zoshter is sitting leaned against their wife (who has reversed her shawl to be blue-out) on the dusty blue living-room couch. Their face is tired.

"Alright; ask away."

"I understand that you're the sole practitioner at your veterinary clinic; is that right?"

They frown.

"Yes, it is."

"And you manage the supplies there yourself?"

"I contract to a software company for digital inventory, and to a delivery service for delivery, but otherwise yes. Look, what has this got to do with Jannami?"

"My oath as a Mediator it's relevant," Dhobrev reassures them.

"Do you recall anything unusual relating to your clinic's inventory recently?"

Zoshter starts to indicate a no with their hand, but then interrupts themself.

"Well, it wasn't terribly unusual, but we did get a bad batch from the supplier about ... two weeks ago, I think? It probably would have been fine, but it arrived with the documentation messed up, and my insurance would have jacked my rates if I'd tried to use it. So I set it aside with the rest of the medical waste for disposal."

"And do you recall what drug this was?"

Zoshter wracks their brain for a moment.

"... I want to say it was an injectable. What were we running low on ... I think it was swimerwudnoicane, but I would have to check the inventory records to be sure."

"I see. Thank you."

Dhobrev takes some notes on their phone.

"Johntaylor, did you have any other questions?"

If John could hear the narration he'd be very pleased that his white trench coat manages to be so distinctive even in another world. In actuality, he is merely privately amused at how the concept of a surname seems so foreign to these guys that his own name becomes smooshed. He kinda likes it though, there's a reason he always introduces himself with his full name. 

"None, thank you".

"Right."

Zoshter rubs at their face with one hand.

"Thank you for your diligence. I'm tired. Get out of my house."

The translation amulet endeavors to convey the sense that this is a perfectly polite way to end a conversation.

In the right (or wrong) crowds, threatening to shoot somebody can be an affectionate goodbye, so the amulet doesn't have to try much. John complies, of course, and after they have exited the house will ask if there's anything he can do to be of use right now.