Family ties. On the trail of Cora Crippen

 Schmidt is a common German occupational surname derived from the German word 'Schmied' meaning 'blacksmith' and/or 'metalworker'. This surname is the German equivalent of 'Smith' in the English-speaking world.
Wolfe. A famous Anglo-Irish surname of Norman-French origins. variant forms Wolfes, Woolf, Woolfe, Woulf, Wulff, Woof, Wooff etc.
 TERESA HUNN , Newport, Rhode Island, America. I am known as Tessie, and am the younger sister of Belle Elmore, whose maiden name was Kunigunde Mackomatzki. She was known at home as Cora. Belle Elmore was my full sister. Our father, who married twice, was a Pole. Old Bailey statement.
Theresa doesn't say their mother was German. Apparently, Dr Crippen only discovered his wife's birth name after their marriage. "She told me her mother was German."
It isn't certain Cora's mother was German. We only know that Dr Crippen said, "Cora told me her mother was German."

1875 Census. 11 year old, Teresa Smith, sister-in-law, lives with Joseph and Mary and their 18 month-old daughter, Concordia. It is definitely written Smith and not Schmidt. Joe,age 24, is listed as a nail Smith and Mary, age 21, a dressmaker. Their surname is spelled, Mackinack. he is listed as an alien, from Prussia.
1882 Births. Mary is listed is listed, Mary Wolf.
1885 Census. Mary is listed, Mary Schmidt Marsenger.
1885 Births. Mary is listed, Schmidt Marsenger.
1893 Births. Mary is listed, Mary Smith Mesenger.

Presumably, Mary included her maiden name (Smith) after her marriage to Frederic Marsenger. The 1875 record also states Cora was 18 months old. Placing her birth at December 1873 or January 1874. It also informs us that Mary, born 1854-1855, had a younger sister, Theresa. Names tend to run in families.
I take a default position with Dr Crippen; he's a liar until proved otherwise. I don't believe Cora's mother was German, or of German parentage - Mary was born in New York. It's a hunch, but I think Mary was of Irish decent. (Scrub this. Seems Mary's parents were German. I've just found them in the 1870 census.) So much for my intuition. Mary was born in New York and their surname is Smith, but probably Anglicised -this would explain why used both spelling variants.

We do not have a definitive answer for what happened to Joseph 'Mackamotski,' although previous writings on the subject state that Joseph died 'when Cora was two'. This would make a date of death for Joseph of about 1875. Beth Erskine Wills 2007, genealogist to John Trestrail.

I found this entry before I read Beth's statement :

Joseph ...Arnecki
New York, New York City Municipal Deaths
Name     Joseph ...Arnecki
Event Type     Death
Event Date     19 Feb 1876
Event Place     Manhattan, New York, New York, United States
Residence Place     New York City, New York
Gender     Male
Age     26
Marital Status     Married
Race     Not Listed
Occupation     shoemaker
Birth Year (Estimated)     1850
Birthplace     Russ Poland
Burial Date     20 Feb 1876
Burial Place     Calvary, New York City, New York
Father's Birthplace     Russ Poland
Whether it is Cora's father, I don't know, but age and date of death fit. I found it interesting enough to file it in my research folder -especially as someone had a difficult job transcribing the surname. 

N.B Mary and Joe Mackinack lived at N Second Street, Brooklyn, Kings, N.Y., 1st June 1875.