I suspect a suicide pact.
But as always - there are asshats like Marcus there with too much fecal matter for brains.
Paraffin test results?
...could be over a boy (?)...if I can’t have him, neither can you (?)
The gun does not fit the MO of a suicide pact for teen girls.
Pills, cutting, head in the oven, jump off a bridge....all pretty common, but the gun thing is rare.