User blog comment:AleximMose/Jonathan Harker In The Hellsing Universe/@comment-829174-20100615180641/@comment-76.5.172.220-20150720063122

It's not unlikely that Kouta Hirano took some creative liscence and changed Wilhelmina's maiden name from Murray to Harker. Personally, I like to put my own spin on it. Examining Alucard as a character, it is entirely possible that he discounted Jonathan's existence out of disrespect, jealously, or even petty dislike. However, if you examine the author rather than the character, it is more likely to assume that Jonathan did not exist at all.