A friend of mine alerted me to the twitter account St.Louis Manifest -- I found the names of my grandparents on this account:

"My name is Luise Klein. The US turned me away at the border in 1939. I was murdered at Auschwitz."

And:

"My name is Leopold Klein. The US turned me away at the border in 1939. I was murdered at Auschwitz."

Also the name of a very dear friend of my mother:

"My name is Ruthild Grünthal. The US turned me away at the border in 1939. I was murdered at Theresienstadt."

According to my mother's book Ruthild and her sister Sybill were killed one of the death marches.

(You can find St. Louis Manifest here.)