This was written write after a science test, so there were no brain cells left. Sorry.
They found the body in Greenhouse 3, tosses behind a dozen bags of dragon manure. No one was sure how long she had been there. No, wait. They did know. Hermione had thrown a fit in the Great Hall and announced, quite loudly, that she was going to Greenhouse 3 at precisely 12: 47 P.M. Everyone had heard her. They also heard the piercing scream precisely eight minutes later. But no one bothered to check it out. Heck, it was a greenhouse. Everyone had screamed at least once in there.
When she did not return to the common room that night, they had all assumed she was studying late at the library.
It wasn't until the following morning, at precisely—bloody hell, who cares?—that they found the body. It was Blaise Zabini who found Hermione. Not that such a fact is important.
At first, no one could imagine who did such a thing. Then they examined the evidence. It was finely deduced that she died of lipstick poisoning. Something that could happen to anyone, of course. It was common enough.
But Hermione didn't wear lipstick. She preferred the natural look.
Rumors of foul play spread through the school like wildfire.
Then someone mentioned walking in on Hermione and Neville in an empty classroom. And we all know what goes on in those empty classrooms. This same student also recalled seeing Hermione crying later on.
Suspicion turned to Neville.
"She wasn't good enough for you!" the mob accused.
"But. . .but I don't own lipstick!" Neville said.
Which was logical. That theory didn't last long. So who would own lipstick?
Other girls. Cho Chang. Fleur Delacour. The Patil twins. Ginny Weasley. Lavender Brown. Any of the many girls passionately in love with Neville Longbottom.
For the angry mob, it was all coming together. The girls were already furious at Hermione for having gotten them all sprayed with plant pus on a former occasion. The empty classroom incident must have been the last straw.
The girls clung together, weeping and declaring their innocence. But it was to no avail.
"Take Cho!" Fleur suddenly declared. "No one likes her anyway!"
As no one did like Cho, the mob and the other girls readily agreed to this. They prepared a giant tub of non-acetone nail polish remover (watermelon scented!) in which to drown Cho.
"Save me, Neville!" she cried. "I love you!"
But he didn't really like her, either.
But before the execution could be carried out, Draco admitted his guilt in a surprising turn of events.
"It was me," he cried, tears falling down his cheek. "I loved Hermione! More than anything! But she wouldn't have me! She only loved Neville. I thought if I framed the other lovely girls, they would resent Neville for this chaos among them and turn to me instead!"
That sounded quite logical, so they forgave him.
It was less competition for Neville, anyway.