The 30-year-old officer, named only as Eduardo N., was killed on Wednesday in the city of Culiacan, Sinaloa.
In 2018, Mexico saw more than 20,000 gun-related homicides. American firearms are "really important to these criminal organizations, who stay in business by the threat of violence," said retired DEA agent Jack Riley.
Defense Department documents obtained by Newsweek show U.S. Northern Command sent an urgent request for additional U.S. forces.
James "Russell" Bolton is reportedly facing at least six charges of extortion and attempted theft.
The report does suggest that violence from Mexican cartels against Defense Department personnel working on the southwest border could increase.
Authorities in the western Mexican state of Michoacan discovered the bodies, believed to be officers who had gone missing a week ago.
The bodies were found close to the city of Nuevo Laredo along the Rio Grande.
"The effects caused by marijuana do not justify an absolute prohibition on its consumption," the court ruled.
As the country battles record homicide rates, it remains unclear who was behind the disappearance of 43 students in 2014.
"There is no better feeling than knowing your science is making a big difference."
The populist politician said 20 unarmed men and women "are going to take care of me."
As President-elect Andrés Manuel López Obrador considers the legalization of drugs in Mexico, he has given incoming Interior Minister Olga Sanchez Cordero a free hand.
The market is expected to grow by 10 percent this year as the annual death toll looks to hit a record high.
Reporter Hector Gonzalez was found dead in the northeastern state of Tamaulipas, notorious for drug-related violence and corruption.
The authorities believe that criminals confused the students with rival gang members.
His wife says her former pimp forced her into colluding with cartels to have him kidnapped following claims that he hacked the Belize government.
MS-13 is among gangs categorized as the biggest threat to public safety based on relationships with Mexican cartels and high levels of violence and transnational crime.
Mexican investigators announced the discovery of more than 250 skulls from unmarked graves in the eastern Gulf state of Veracruz.
The killings marked some of the worst abuses by Mexico's security forces in a decade of grisly drug-related violence.
The cartel involving 11 firms operated for six years and were fined up to €56 million.
The 49-year-old former teacher is wanted for the 2009 murder of 12 Mexican federal police officers.