wlan contains <NAMEofNETWORK>, or
wlan.ssid == "NAMEofNETWORK"search inside the filtered packets for suspicious strings.
((wlan.ta == e8:de:27:16:70:c9) && !(wlan.fc == 0x8000)) && !(wlan.fc.type_subtype == 0x0005) && !(wlan.fc.type_subtype ==0x0004) && !(wlan.addr==ff:ff:ff:ff:ff:ff) && wlan.fc.type==2
wlan.addr==<MAC address> && (ftp || http || ssh || telnet)to filter its traffic. Note that ftp/http/ssh/telnet filters are useful if you have decrypted the traffic.