A date rape drug? That is mostly media hype -- there isn't really a classification of drugs by the DEA or other agency of Date rape drugs.. Rophynol , GHB, and Ketamine are the most common of the "date rape drugs". They work by disassociation of the brain/body. Which basically sedates the person but keeps them awake physically and very dis-inhibited (beyond what alcohol does).
To get an idea of them check here:
Rophynol - http://en.wikipedia.org/wiki/Flunitrazepam
GHB - http://en.wikipedia.org/wiki/Gamma-Hydroxybutyric_acid
Ketamine - http://en.wikipedia.org/wiki/Ketamine
GHB would be the easiest to obtain -- though none of them are particularly 'easy' to obtain. None are prescribed with any regularity, and ketamine is used primarily in vet. Medicine.
At any rate, other chemicals can create disassociative effects. IE: If someone were to ingest a diluted mixture of propyl ethylene glycol (anti-freeze) They would have strong neurological effects, and potential bleeding with organ damage (possible). Though the bleeding is something that is throwing me off here. It isn't particularly common or 'easy' to cause internal bleeding with a sedative drug.
However, it is certainly possible. The most likely scenario with bleeding would be alcohol being mixed with aspirin, or even something like DXM (cough medicine, over the counter).
The alcohol would irritate the stomach lining, but more importantly thin the blood. The second ingredient would be what would create the bleeding, .. though alcohol can do it alone.. it certainly takes a very high quantity (is common in moderate to late stage alcoholics).
The only way to know here is to get a Toxicology screen within 24 hours of ingestion.. Preferably blood Tox screen.. If it has been more than 24 hours, then you will never know (unless he for some reason decides to reveal things) what she ingested.
That is the sad fact.
That said, as others say -- this needs to be investigated. Though, be careful you and her (and all involved) in assuming guilt on his part. This is slander, insinuation of intent to harm, rape and so on. Very serious accusations and charges without proof. Legally it can backfire. So the key would be to stay away from this person. Again, remember without proof there is nothing legally that can be done. The police can do nothing.
However, filing a police report wouldn't be a bad idea just to have a history of it on file. It won't do anything now, but if something happens in the future with her (Hopefully she has enough sense to not associate with him any more) -- or with ANOTHER person/girl and this guys name the police will have more than enough motive to investigate, etc -- because of this previously filed report.
Make sense?
So take care of her mentally, physically, and make plans to stay away from the potentially ill-in tented guy.
Take care,