Little explanation has been given as to why Sgt. Andrew Tahmooressi, a U.S. Marine reservist, has been jailed without trial in Mexico for over three months.
Tahmooressi was arrested in Tijuana on April 1, after driving into Mexico in possession of three firearms.
Contradictory accounts of Tahmooressi's case have since emerged, and he claims the border crossing was accidental.
On Thursday, Mexican diplomat Ariel Moutsatsos-Morales spoke to "New Day" about legal jurisdiction in Mexico.
Moutsatsos-Morales also shed light on some of the questions looming around Tahmooressi's arrest.
Referencing a number of signs placed along the U.S.-Mexico border, the official expressed skepticism of Tahmooressi's professed obliviousness.
"The signs are very clear," he said to CNN's Chris Cuomo. "He certainly made some decisions on the way to crossing into Mexico."
According to Moutsatsos-Morales, the signs plainly mark each country's border, while other warnings indicate that weapons and ammunition are forbidden in Mexico.
He also outlined the discrepancies between U.S. and Mexican law, clarifying why Tahmooressi's case has yet to be tried before a Mexican judge.
"In the U.S., you have prosecutorial discretion - a prosecutor can decide whether to prosecute something or not," Moutsatsos-Morales said.
"In Mexico, that doesn't exist. If there is evidence of a possible crime committed, like in this case, the prosecutor has to prosecute."
But Mexico's judicial system bears some semblance to that of the United States', where a judge - not a prosecutor, public opinion or an elected official - is responsible for determining proof of guilt.
"He's in the hands of a Mexican judge in a Mexican federal court and not in the hands of the government," Moutsatsos-Morales said. "That is very important for the American people to know."