update and correction: unknown gunmen have killed two excavation workers, kidnapped two archaeologists in Nigeria
Unfortunately, there has not been any more news on rescue efforts yet. However, I have found more reports with more details, so I have updated my post. Most importantly, I thought that the killed hunters had been security escorts, but other reports have shown that they were excavation workers. So, it is the case that five still-unknown gunmen (two with machetes, three with ‘heavy guns’) have killed two excavation workers, kidnapped two archaeologists in Nigeria. Most of the new information comes from interviews of Sani Aliyu and Usman Kagarko by Premium Times.