Of course go to the police station and inform the policemen about the intruder. Once they leave the station, give the count his medicine and approach the second section (customs) window. You have to get the address of the woman who pays visits to Brigs' grave. The customs officer mentioned that there's a package waiting for her. Open the window and take a look at the table right next to it (on the right; zoom). There is a fishing rod - borrow it for a while. Go out of the zoom ant take a look at the table on the left (zoom). Try to reach the package, but it's too far. Use the newly gained fishing rod to reach it.
Take a look at the package and notice the annotation telling to deliver the parcel to a different address (it seems that you can get to the woman's house from two sides).