aur key not found, attempting to locate packages that use that key

i tried to do an upgrade today and got an error about 2 keys I am trying to figure out which packages are causing the error so I can either delete them or gather the key file for them. downloading required keys... :: Import PGP key 139B09DA5BF0D338, "David Runge "? [Y/n] y error: key "139B09DA5BF0D338" could not be looked up remotely :: Import PGP key F4AA4E0ED2568E87, "Jiachen YANG "? [Y/n] y error: key "F4AA4E0ED2568E87" could not be looked up remotely error: required key missing from keyring