windows 7 - Identify an unknown IP in our network

I have a network containing 20 clients. I assigned IP range 10.0.0.1 to 10.0.0.20 to them. When I do an IP scanning I see someone using 10.0.0.131 in VMware. How can I find out which IP is this IP bridged with? i.e How can I find out which system has 2 IP? (i.e the other IP of this system)

Update:

My system IP in the network is 10.0.0.81:

Output of the IP scanner show someone using 10.0.0.131 in VMware:

And the result of tracert command show nothing between us:

C:\Users>tracert -j 10.0.0.131 10.0.0.81

Tracing route to ghasemi3.it.com [10.0.0.81]
over a maximum of 30 hops:

  1    <1 ms    <1 ms    <1 ms  ghasemi3.it.com [10.0.0.81]

Trace complete.
C:\Users>