Looking for gravesites and family information of Tomasz and Marianna Kowalski possibly from Szczepkowa, Poland

Hello, I am trying to find family of mine connected to Tomasza and Mariianny Kowalski ( possibly Krupienska/ Krupienski) maiden name. They are my great grand parents. I found their names on a copy of my grandfathers birth certificate. It shows the town being Szczepkowa and the Parish as Grzbesk. I have a friend in Kunow who called a priest at this Parish but he would not give any information since he was not family of theirs? My grandfather Jan Kowalski was born in 1884 and came to the US in 1904. I do not have any info on my family in Poland except for the copy of the birth certificate that was issued in 1938 so my grandfather could become a citizen of the US.. My grandfather Jan died in the US in 1958 and my father believes he was told that Marjianny was still living in Poland. So the timeline for Tomasza and Marjianny would be late 1800 to 1950s. My grandfathers ship papers list Rzewin as the town he came to the US from in 1904. My father thinks he was living with someone learning a trade away from his family possibly. He spoke of Mllawa often. And their should have been a few other siblings. I think he had a brother who also came to the US a few years before he did and possibly his name was Antoni. And there might have been another brother and sister who were in Poland. Any help would be greatly appreciated. I am planning a trip to Poland in this next year and would love to connect with family if there is any. Thank you, Brad.. babblingbrook66@gmail.com

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