Speaking purely from a stance of plausibility:
The next logical investigatory step will be looking for commonalities between the victims or the attacks themselves. The officer is not likely to lend much credence to supernatural seeming events being connected at this point, so they will probably focus just on things that seem similar to the werewolf attack, assuming the others are weird, but unconnected. Things like location of the assault, known associates, places the victims may frequent, etc, would be of special interest.
If there are survivors of these attacks, interviewing the survivors would be expected.
Standard police procedure would probably have a decent chance of finding a typical werewolf's haunts - They attack one or more times per full moon, they have a fairly static territory, and they aren't generally super sophisticated about stuff like trying to pick victim in new locations.
If the werewolf isn't apprehended, it's still almost certain that the investigation would yield a decent idea of it's territory.
The officer would then likely proceed by staking out this territory - Whether or not they do so adequately prepared to take on a werewolf is going to hinge strongly on their gullibility, and how creepy the investigation has been up to this point, but it's not super likely that they'd be prepared for a supernatural encounter.
All in all:
- Chance of finding werewolf: Plausible
- Chance of finding anything else supernatural : Negligible
- Chance of believing in anything supernatural prior to encountering werewolf: Negligible
- Chance of surviving encounter with werewolf : Negligible