View source for Did Aaron Kosminski have any brothers or sisters?

Yes, Aaron Kosminski had 6 siblings, although Pessa had died before he was born.

Aaron’s Father: Abram Josef Kozminski
Aaron's Mother: Golda Lubnowski

{| class="wikitable"
|Pessa
|Female
|December 1845, but died before reaching three years of age
|-

|Hinde 
|Female
|November 1848
|-
|Iciek (later called Isaac) 
|Male
|1851
|-

|Malke  (later called Matilda) 
|Female
|1854
|-

|Blimbe 
|Female
|1857
|-

|Wolek (later called Woolf) 
|Malre
|1860
|-

|Aron (Later called Aaron) 
|Male
|1865
|-

|}

[http://crimehub.co.uk/index.php?title=Aaron_Kosminski_-_Suspect You can read more about Aaron Kosminski here]