Time to channel my inner Phoenix Wright.
An elderly man, Ellis Smith, in a motorized wheelchair is sleeping outside of a vacant Hooters.
---If he's wealthy enough to afford a motorized wheelchair, why was he sleeping outside a Hooters?---
The alleged attacker, Josephine Smith, 22, pounced on Smith, biting his face, and announced that she was a vampire. Smith has no criminal history, while Ellis has had 12 arrests over the past four years.
---A college girl with no criminal history, for no reason, attacks an old man, severely mauling his face with her teeth, and announcing that she is a vampire. First, vampires go for major arteries, like the jugular, the veins in the wrists, or the vein in the inner thigh. While it is true that head wounds tend to bleed a lot, if someone was to snap and believe they were a vampire, and to go so far as to actually attack someone, they would most likely conform to the images of vampires that have been drilled into their head by years of exposure to Hollywood vampires, not turn into some animal that eats peoples faces. That sounds more like a zombie than anything.---
Ellis survived the assault, and managed to get to a nearby gas station, where he phoned the police.
---Somehow, a 69 year old man was able to fight off a 22 year old woman while she was busy ripping his face off with her teeth. He was also able to get to a gas station without her following him. No wheelchair is faster than a running person, just as no elderly man would be able to fight off a young woman in the throes of a presumable bloodlust.---
When police arrived, they found Smith near the scene of the attack covered in blood, without pants, and with her panties around her ankles.
---As was mentioned before, head wounds tend to bleed a lot, which would make the fact that she was covered in blood not much of an issue. However, the fact that she had her panties around her ankles is rather suspect, as is the fact that her pants were simply gone.---
There were no witnesses. Smith was unable to explain the attack or why she was partly au naturel.
---And here's the clincher. Smith allegedly announced that she was a vampire while she was attacking Ellis, but was unable to give a reason for the attack when the police questioned her. Presumably the police arrived not long after Ellis phoned it in, which means if there were any drugs in her system that would have made Smith delusional and aggressive, they would have still been in her system. Instead, she is confused and has no explanation for her alleged actions. Since there were no witnesses, there is no way for anyone to dispute Ellis' claims.---
Conclusion: It is my opinion that Ellis was the one who attacked Smith, drugging her and probably molesting her, if not outright raping her. Just because he's in a wheelchair doesn't mean he's not still functional. Smith, realizing what was happening, fought back against her attacker. Ellis fought her off, which would have been easy because of her drugged state, and motored over to the gas station, calling in a fake attack, with a bit of vampirism thrown into his story, to make the police think they were dealing with a run-of-the-mill druggie, and discount anything she might say as delirium or an attempt to switch the blame onto Ellis.