DOMZAL (ДОМЗАЛЬ)

Would it be possible to find my Grandmother's grave if it is now, to all intents and purposes, unmarked? Would you be able to 'excavate' the sites of any graves that are under big trees, but which have no obvious markings to find the plaque, or remains of it, that was placed over the grave in 1944 (?), as this would be the only tangible proof of the grave. Also, would you be able to find my Grandmother's death certificate in the town's Registry/Archives or the local Catholic Church's records?

Family Name: DOMZAL, ДОМЗАЛЬ (RU)
Name: Wiktoria
Period: 1944

Buried at the Roman Catholic/Christian Cemetery in Nowogrodek in May 1944 under a large tree, with no gravestone or vertical cross to mark her grave, just a relief plaque (made of wood or metal?) of the Virgin Mary which was placed horizontally on the grave. No other grave markings known and, as the plaque has probably sunk down in the last 72 years, would you be able or allowed to dig down a little to recover it, if it has not rotted or corroded away?