I would say your best path for research unless you know names of specific survivors/victims would be to look into the Yizkor book of the town. The Yizkor, or memorial books were written by survivors post-Holocaust, gathering together names, survivor testimonies, and stories and histories from the village. The best ways to access these books are through the New York Public Library and a website called JewishGen which is very helpful in general for Jewish ancestral research. I use it a great deal in translating survivor testimonies in order to cross reference accounts and find family members. Most of these books are originally in yiddish, and reading some would require help from a yiddish reader, however, many of the books, including the main books for the city of Łódź itself have sections or the entire book translated to English on JewishGen. Feel free to reach out if you need any help! I am very familiar with this site and read yiddish at an intermediate level.