Mexico has launched an investigation after a video was made public appearing to show one of its soldiers shooting a man dead at point-blank range.
The alleged extrajudicial killing was caught on security cameras in Puebla state.
The footage emerged in local media, a week after a major clash between security forces and suspected oil thieves in the same town, Palmarito.
Four soldiers and six alleged criminals died in that incident.
The new video shows soldiers opening fire on a car carrying suspected oil thieves, before one of them is pulled from the vehicle and seemingly shot while lying on the ground.
Mexican media said both incidents happened on the same night, 3 May.
The defence ministry said in a statement that federal prosecutors should “comprehensively clear up” what happened.
The ministry also said soldiers had come under fire from the vehicle.
Mexico’s army has been embroiled in a number of scandals in recent years and its work in communities – working against criminal gangs – is hotly debated.
Earlier this week, an international think-tank released a report ranking Mexico as the world’s second deadliest after Syria.
The annual Armed Conflict Survey, by the London-based International Institute for Strategic Studies (IISS), based their report on the number of homicides last year.
The IISS report said that Mexico’s drug cartel-fuelled violence had claimed 23,000 lives in 2016, more than the violent deaths in Iraq or Afghanistan during that period.
The Mexican government rejected the findings.
A joint statement by the Mexican foreign and interior ministries criticised the IISS’s “uncertain methods”.
It said the existence of criminal groups and the use of the army for domestic security did not mean the country was in armed conflict. It also said not every homicide in the country was related to fighting criminal organisations.
Mexico says that the country’s homicide rate is lower than that of other countries in the region, including Honduras and Venezuela.