Does anyone know anything about Anna monivenaro AREHO?

Hi my family are trying to find information on Anna monivenaro AREHO who died in 1987 in a boating accident we think it was in the Lae River. We need to find information such as her date of death, her death certificate or even a photo of her grave site with her name and date of death clearly visible. If anyone could provide these details we would greatly appreciate your help.