Just saw this post and you may already have loads of information about Ed Cassidy. My grandfather was Edward Cassidy, born in Donegal, Ireland in October, 1889. He died in 1972. However, he was not a policeman in Virginia. He worked for the Pennsylvania Railroad; his son, my father (also Ed) lived in Virginia (but not a policeman). From what I understand, my grandfather and his brother George were the only children of Isabella and George who did not immigrate to Australia, so your cousin probably kept in contact with Ed's other siblings in Australia as well! I have created a family tree on this site with loads of info and a few pictures. I will attempt to attach a picture of Ed (my pop pop)!
Thanks, Pat Cassidy Barr