Police officers at Mexican border state in Tamaulipas are under investigation for the case of the kidnapping of two underage teenagers.

The police officers are accused of delivering the minors to members of a cartel.

The said underage teens are still missing and relatives and locals demand the return of the kidnapped teens, according to a Breitbart exclusive report.

The two minors were detained by Tamaulipas state police officers last week for a traffic violation in Ciudad Mier. The police then took them to the nearby border city Miguel Aleman, where they were said to be released to the Gulf Cartel.

Relatives and locals in Ciudad Mier held protests and were demanding the safe retrieval of the two teens. The said minors were aged 14 and 13-years-old, according to another Breitbart report.

Due to the case, residents blocked the main highway in Ciudad Mier that runs through the city.

It remains unclear if the missing teens are connected to or worked as lookouts for one of the criminal groups that operate in the area.

Authorities did not yet release an official version of the events.

Related story: Notorious Mexican Cartel Leader Using Children as Shields in Gang War

Investigation of the Events

The case triggered an investigation to the highest level in the Tamaulipas government. The sources said that there is a particular significance regarding the location of the arrests and where the victims were transferred.

Ciudad Mier is an area under the operations of the Cartel Del Noreste faction of Los Zetas, according to U.S. law enforcement sources in Mexico.

The current guess of Tamaulipas investigators suggests that the teenagers were working with the XDN-Los Zetas in some capacity.

Cartels Turning to Kidnappings

A record of 1,700 kidnappings occurred in 2013, according to data from the Mexican National System of Public Security.

Kidnappings fell briefly in 2015, with a recorded number of 1,069 kidnapping case. However, numbers are starting to climb once again with about 1,200 kidnappings that took place in Mexico in 2017.

Between January and March 2018 alone, almost 400 people were reported to be kidnapped. The increase in kidnapping cases in Mexico is part by the insatiable U.S. demand for drugs, according to a Vox report.

Criminal groups began using kidnapping around the start of 2006. Research professor at the Autonomous University of Coahulia, Victor Manual Sanchez Valdés, said that ransom money is being used to fund kidnapping activities.

"They had to find other sources of income, which gave the hitmen in these groups carte blanche to participate in activities like kidnapping and extortion," he was quoted on a report.

Valdés also said that kidnapping methods have also changed, saying that express kidnappings, in which victims are taken for a short time until small payments are met, have become more common in recent years.

In 2016, the National Institute for Statistics and Geography in Mexico shower that express kidnapping is made up of 66 percent of all kidnapping crimes.

Related story: DEA Seized $35 Million Cash, Ammo, Drugs From Suspected Mexican Cartel Members