Apart from Veronica's personal friends Marge and Janice, George seems to be the only one who knew Veronica "might" be out drinking. She whispered that in his ear shortly before he left for the ball. Haley verifies that story in so far as that she sees her mother whispering into George's ear. V. had told Elizabeth previously, she would stay at home and relax.
If V. was killed, the murderer (X) could not have known she was going out unless:
- X had access to information through V's friends
- X had observed Veronica leaving her home (but couldn't know where she was going)
- X had been informed by Veronica (or George) that she was going out
- X is George
The killer, who must have planned the murder as a suicide, has a big problem: time. The murderer would have just under an hour to do it - between around 9 pm and well before 9.50 p.m. (guessed e.t.a Haley and George)
- X had to wait, and/or prepare (2 hours)
- X didn't know when V. actually would return
- X didn't know when George and Haley would return (unless George was in on it and bided time by "mingling" and/or warned X with a signal, like a short phone call.)
This seems to be rather a very high risk for the killer, based more on chance/luck rather than cunning and timing. The more likely scenario still seems to be Veronica arrives home and commits suicide in a quick, clean and efficiant way, before the return of George and Haley. As the phone call of George was not answered and the bar presumably was not that far away, perhaps she was already dead before 9.30 pm.
Prove all things; hold fast that which is good. (1 Thess 5:21)