Officials say the three tourists killed in Mexico were believed to have been attacked while trying to prevent their vehicle being stolen.
The bodies of Australian brothers Callum, 33, and Jake Robinson, 30, as well as American Carter Rhoad, 30, were found at the bottom of a well in Baja California state after a days-long search.
According to Baja California state prosecutor Maria Andrade, it's believed that the attackers were trying to steal the tyres from the vehicle and shot the trio when they resisted.
Their bodies were found in a 15ft deep well on Friday, each victim had been shot in the head. Authorities found a burnt pick-up truck, abandoned tents, and a phone nearby.
Three people have been detained by police in suspicion with the attack.
A fourth body was also found in the well, unconnected to the case, officials confirmed.
The 35-year-old UN peacekeeping mission in the Western Sahara region will come to an end after the Security Council failed to renew its mandate, the UN chief said on Sunday.
Ukraine's military said it evacuated 167 people from threatened areas of southern Kherson region on Sunday as a temporary local ceasefire expired, two days after buses carried residents out of the Russian-held town of Oleshky.
Israeli strikes have killed at least eight Palestinians, including five police officers, in the Gaza Strip in two separate attacks on Sunday, according to medics and the interior ministry.
The four members of a crew who took part in a simulated mission to Mars have emerged after 378 days in isolation at the US space agency's Johnson Space Center in Houston, an endeavor designed to help prepare for a possible future excursion by NASA astronauts to Earth's planetary neighbor.