If Alucard is able to obtain vampire blood from any of the other vampire, or has had contact with them prior to investigating, then he would be able to find that the blood signature is most likely that of a vampire's due to similarities. The guards would recommend speaking to one of the three Ikorran witnesses listed above, each of whom might've seen or heard something unusual over the past week or two.

Alucard would be able to sense a similar energy. It appears that the Summoned are capable of doing so while the natives are not.