I noticed on the site it talks about whether Mrs Columbo is real. I think the biggest evidence has been missed. At the end of Rest in peace Mrs Columbo he is alone on the phone and talks to her in an affectionate manner. This is the only time I can recall this type of conversation with his wife.
And I nearly forgot the biggest evidence of all. In identity crisis Nelson brender bugged his house. He knew Madame butterfly was his wife's favourite piece of music.