I saw an episode of a TV episode a few years ago. I've asked about it on other sites and got almost unanimously pointed to Supernatural. However, I've been watching Supernatural and I'm up to season 7, and I'm pretty sure I'm up to episodes that aired after I saw this other episode. Here's what I remember:
Young girl (anywhere from 9-14) is helping an older woman (aunt? grandmother?) tend to plants in a greenhouse. Older woman leaves. A deranged-looking man shows up. Confidently, the girl asks the guy if he thinks he's going to try to sexually assault her, in some sarcastic way. The guy's plan was exactly that, so it would seem, so he chases after her.
A couple people (guys, I think, but could have been a guy and a girl) are from out of town and are interviewing people in town. It's a woody town, somewhere up north. No idea where. Could be Oregon, could be Montana, could be Vermont. They interview people (the girl's parents?) in a house and they interview a local business owner in a general store.
At the end of the episode, a guy closes a trunk lid to a classic car. I don't remember the color, the make, or the model. I think I remember them putting someone (a body, a living person like a suspect) in the trunk, but I can't be sure.
Like I said, sounds a lot like Supernatural, especially if the car in #3 is a black '67 Impala and the people in #2 were two brothers in their 20s/30s. Both are possible.
Thing is, I was at my brother-in-law's place, and it sounded like a cool episode. It got me into Supernatural, and even though I didn't get a hit, I'm enjoying the show. The show I remember didn't have angels, or demons, but there was a supernatural element to the crime. I vaguely remember maybe the plants were special, or maybe the girl had the a terrible secret trope, like a monster in disguise or something. Or maybe the guy was the monster. Anyway, the curiosity is bothering me, so I thought I'd cast a net.
I am ruling out Supernatural because, as I said, I'm caught up to episodes that aired after this episode was on TV (in 2009-2011 or thereabouts). I know Buffy and its spinoff Angel are supernatural investigative shows, and they're on my watch list, but because they're more juvenile and, I assume, more for girls (?), they're far lower on my priority list. Even Supernatural was down a ways, but I bumped it to look for this episode (and I'm glad I did).