According to an Incident Report

As AP News released a report last June 7, five men were slain by the soldiers as caught on camera. Tamaulipas State Law Enforcement received a report and was sent to the incident location at 2:41 pm on May 18. Initially, they have seen wounded people and others dead.
At 3:11 pm forensic workers and state investigators arrived. They found two white pick-up trucks and lots of shell casing were scattered on the ground. Sixty meters away from the shell casing, the black pick-up truck was found against the wall and the concrete wall was separated by the pick-up truck. All four doors of the pick-up truck were open, and there were also four bodies found wounded. At the hospital, the fifth victim was found with three bullets wound.
Caught on the security from a store, the pick-up was fully accelerated, crashing the wall in Nuevo Laredo, across from Laredo Texas. The pick-up truck was being followed by the military and ran into the passenger’s side of the pick-up truck. The men from the military truck dragged the passengers out of the truck, kicked, and forced them against the wall. Which, the pick-up truck passengers were later found dead. After then, the soldiers get back to the road, one of the soldiers picked up the guns using a red bag to avoid leaving fingerprints.

Authorities’ Investigation in the Crime Scene

According to President Andrés  Manuel López Obrador, a loyal supporter of the armed forces insisted that those responsible men will be turned to authorities. Pres Obrador has given the military a role in everything, from the law enforcement, infrastructure projects, and even running the airports and trains. But there were filed complaints showing human rights abuse.
An associate professor at George Mason University name Guadalupe Correa-Cabrera who studies the incident’s different angles said that the soldier are trying to lure the investigators to a different angle of the crime. They are trying to show in  the crime scene that there was an armed confrontation between the two parties.