Do You Know if You've Been Spiked?

Police say they have records of two cases of penetration by a needle, confirmed by medical professionals. Toxicology reports still haven't come back so we don't know for certain whether those victims were spiked. For that many attacks to be happening at once, we'd be seeing at least some confirmed cases. It's equally likely that at least one of the victims would have caught the injector red handed, holding a syringe. No one ive poken to has seen anything like this, not while they were being injected, not even on c c t v. The more i dig into it, the less likely it seems. All of this begs the question, what actually is happening? And