According to Shaun Eli :
I think that the molding was ripped and that's why it was scrap-- they
used only a portion of it. Thinking about it, though, I'm not sure it
was wood as it was rather light for an eight foot (give or take)
piece. Do they make plastic molding that looks like wood?

They make PVC, foam and MDF moldings.

PVC molding is quite "floppy" and solid color (usually white) throughout.
If you handled it, I think it would have been almost impossible not to
notice it was plastic, and it weighs considerably more than pine. I
don't think it can be flung in such a way to stay straight.
It'd be almost like trying to fling cooked spaghetti. Indeed,
it wouldn't be sticking straight out of your wall, it'd be
at least partially "flopped", if not draped right against
the wall after it'd seen the sun for a few minutes.

PVC molding is generally not made in particularly large sizes,
and it generally isn't very attractive. Most often quarter
round or inside (cove) molding, but there are 2" or so baseboard
moldings commonly available. Larger moldings are available, but
a lot rarer.

You'd normally use PVC in places where you're worried about dampness.
I've used it in a basement bedroom, and trimming out a built-in work
bench used for wine making in a basement utility room - don't have to
worry about stains.

Since PVC trim is solid color throughout, it wouldn't show
the "wood colored edge" your pictures seem to show.

I've not handled foam moldings, but I don't think you could miss it if
you handled it either. Very light. I'd assume it would be much more
floppy than PVC. It sometimes comes in rolls. It'd be impossible
to drive it through cedar at any even marginally probable scenario,
and if you could, it'd probably be draped right down the face of the
shingles. It'd be blowing in the breeze.

There is a lightweight MDF trim as well as a more "normal" weight MDF.
The former is lighter than pine, and the latter is considerably
heavier. (The light stuff might not "officially" be MDF, but it's
called that). Pre-primed MDF trim of both types is _very_ common
and quite cheap - usually considerably less expensive than "real wood"
moldings. (I've used rather a lot of the stuff, because it's cheap
and machines/paints well. But it's inadvisable in damp areas.)

MDF is more "floppy" than pine, but not so floppy that it couldn't
be flung like pine trim could. It would appear rigid when stuck in
something.

If you saw "under" the MDF priming (eg: ripped edge), the cut edge would
look much like (in color) what your pictures seem to indicate.

Note, however, that the pre-primed MDF trim I've used is not
primed on the back, and people generally don't paint the back
of their trim. Your stuff appeared to be primed on the back.

There are also a few types of "wrapped" trim. Most usually finger
joint pine or MDF that have what you'd describe as a paper or
foil wrap on the "good side". Usually advertised as "pre-finished
trim", usually either plain white or a oak grain pattern on MDF.
But if you handled it, I think it'd be difficult to miss. The
wrap generally doesn't extend more than 1/8" or so around the
back, and your trim doesn't look like that.

I did leave the detective a message but he hasn't called me back yet.
I'm reasonably sure that if I call him next week I'll be able to reach
him. I live in a small town and it's not like he's too busy
investigating murders to bother talking to me about molding. Plus, he
found it a bit interesting as he said he's worked construction.

If he calls, suggest "saw kickback or thrown from the third floor" and
see what he thinks of that idea.
--
Chris Lewis,

Age and Treachery will Triumph over Youth and Skill
It's not just anyone who gets a Starship Cruiser class named after them.