How to ping and pinpoint location of intruder’s MAC Address?

I already blocked an anonymous IP and its MAC Address who ride on to our network but still manage to get through my computer via Remote Port 2850 to my Local Port 445 as can be seen on the traffic log of the firewall & detection system. How can I ping the MAC Address of that intruder’s computer and pinpoint the location to catch the perpetrator who make my computer very slow and compromise my internet browsing?