Hei Riita,
My response is more suited to the surname Kannus rather than Koskela.
My great-grandfather, Antti Kannus was born in Sievi on 3.9.1871 and died in Spencer, NY on 16.11.1960. He immigrated to America in 1890. He did have a brother, Heikki who was born in Sievi on 22.11.1885, immigrated to America in 1903 and died 20.6.1937 in America.
Antti did have a number of brothers and sisters who we believe stayed behind in Finland. The names that I have are as follows: Hilma Johanna, Elisabeth (Liisa), Paulina, Jaakko, and Hilda Kustaava. I have all of their birthdates and deaths also.
As you know, there are very few people with the name Kannus. As I understand it, the place where the records were kept in Sievi burned down and all the records prior to 1939 were lost in the fire. This is one reason it is so difficult to trace family members fom Seivi. I am told that the Kannus family was originally from Karelia but I cannot verify that as a fact.
I am in contact with Kalevi Kannus and his wife Marjatta who live in Turku. They have been most helpful to me in my search. We belive that we are somehow related as cousins.
It would be a pleasure to hear from you to see if perhaps, we have a common interest. Thank you.
Bob