I have been doing a bit of digging into the red hot poker murder.
I have found as follows.
The perptrator was Henry Cowx of Maryport, the victim his wife Ann, also of Maryport, both were residing in Douglas.
Not sure when incident took place but first commital was 18th March 1809.
Henry and Ann appear to at least have a Son Henry, born 1795 in Maryport.
So far unable to track down the link to John Cowx, any suggestions anyone.