The Rio Grande is the fourth-longest river in the US. It originates in the Colorado Rockies, then bends and winds its way through New Mexico and along the edge of Texas. Nearly 2,000 miles later, it empties into the Gulf of Mexico. For more than half of its length, the silty-green river serves as the official southern border for the entire state of Texas.
It's also a place where migrants drown every year as they try to make it to the US, according to US Customs and Border Protection.
Oscar Alberto Martinez, 25, and his 23-month-old daughter fell victim to the river's currents in late June. A haunting image, captured by photographer Julia Le Duc, shows the two lying face down in the reeds near Brownsville, Texas. Martinez's daughter is tucked inside his black T-shirt with her arm slung around his shoulder.
Martinez had traveled north from El Salvador with his daughter and wife Tania Vanessa Avalos, 21, according to Le Duc, who is a reporter for the Mexican newspaper La Jornada. They'd been waiting in Mexico for two months hoping to come to the US and ask for political asylum. Desperate to get to the US, however, they decided to swim across the river instead of continuing to wait in Mexico.
Their deaths are a tragic reminder of the lengths people will go to in order to reach the US. Their story isn't unique. Honduras, El Salvador and Guatemala are some of the most dangerous countries on Earth because of violent organized crime, cartels and gangs. It's caused hundreds of thousands of people to flee. Customs and Border Protection says it apprehended nearly 500,000 migrants between January and May, up 117% from the same period last year. To catch these migrants, the agency monitors the border with a complex network of cameras, drones, sensors and surveillance technology.
Asylum seekers are considered legal immigrants under US law. And up until last summer, they could simply show up at a US port of entry to begin their application process. But now, under a new government process called "metering," only a limited number of asylum requests are allowed per day. Immigrants are being forced to wait in Mexico indefinitely.
Once a person sets foot in US territory, they have the right to apply for asylum. So, by braving the river, migrants can jump that endless metering line.
Martinez and his daughter's bodies were returned to El Salvador on Sunday and are reported to be buried on Monday. The country's new president, Nayib Bukele, said in a news conference on Sunday that El Salvador is to blame for the exodus of its citizens.
"People don't flee their homes because they want to, people flee their homes because they feel they have to," Bukele said. "They fled El Salvador, they fled our country. It is our fault."
President Donald Trump has made it clear that he believes a big part of the solution to stemming immigration is to build an 18- to 30-foot cement or steel wall on the US southern border. Other politicians, like Republican Texas Rep. Will Hurd, say a "smart wall" built with technology would be a cheaper and more effective solution.
Border Patrol agents say they've already been using technology to police the region for decades. And new innovations are popping up regularly with federal money pouring into border tech. A congressional spending measure, passed Feb. 14 and signed by Trump, awarded $100 million in technology funding to the Border Patrol, with an additional $112 million for aircraft and sensor systems.
Immigration advocates say, however, that neither a physical wall nor a smart wall will necessarily solve the issue.
"It's not gonna fix it," Jodi Goodwin, a Texas immigration lawyer, said in an. "If you wanna stop people from coming, you have to stop the factors that are pushing them out of their homeland."
Here's some of the tech the US government is using to patrol the border:
Drones range from noisy quadcopters to massive payload-carrying mini-planes. Customs and Border Protection has used military-style Predator drones to monitor the border since 2006. These $16 million unmanned aircraft can fly as high as nine miles and are equipped with radar strong enough to detect footprints in the sand.
The Department of Homeland Security is also looking into flying smaller unmanned drones on nighttime border missions in West Texas. Called the RQ-7 Shadow and made by AAI Corporation, this drone uses an array of cameras, lasers and radars to "locate, recognize and identify targets" up to 75 miles away. It then beams that information back to a ground control station. The devices have been used in Iraq and Afghanistan.
Border Patrol relies on a network of buried seismic ground sensors to detect vehicle movement and people's footsteps crossing the border. When one of these sensors is triggered, it'll send a signal to local Border Patrol headquarters. Agents then go to the location and investigate. The sensors, which have been around for decades, aren't able to tell what exactly set them off. The input is the same from an animal, person or vehicle.
Some new Silicon Valley sensor companies are also going after Border Patrol contracts. One such company, Quanergy, has been testing a lidar sensor -- the same technology used in self-driving cars -- to measure distances, scan for movement, and create 3-D images of people on the Texas border. The company says its sensors can tell the difference between a person and an animal.
The US southern border is lined with Border Patrol camera towers. In areas of high activity, the 120-foot-tall steel towers are topped with a system of daylight and infrared cameras that point up and down the international boundary. Border Patrol agents back at local headquarters monitor the footage from these cameras. Some displays are in black-and-white, while others are in infrared or color. Along the Rio Grande, the agents are looking for people swimming across the river or traversing it in canoes, inflatable rafts or inner tubes. If they see anything suspicious, they immediately radio agents in the field.
In Arizona, an Israeli company called Elbit Systems built 43 high-tech camera towers that can capture images up to 7.5 miles away. Customs and Border Protection awarded the company a $145 million contract for the towers in 2014.
Machine learning artificial intelligence is one of the newest technologies to be introduced at the border. Anduril -- named after a magical sword in Lord of the Rings -- uses a system it calls Lattice that can process inputs from hundreds of thousands of sensors strategically placed along the border and then use artificial intelligence to instantaneously interpret that data. For example, Lattice can continuously monitor one stretch of desert, and the moment it detects anything out of the ordinary, like a vehicle pulling over or a group of people walking, Border Patrol will be alerted.
The company is headed by Palmer Luckey, the 26-year-old co-founder of Oculus VR who was forced out of Facebook. Anduril has a contract with US Customs and Border Protection in California and is testing its tech on a private ranch in West Texas.
Aerostats look like big white blimps floating 5,000 feet up in the sky. They're one of the surveillance tools Border Patrol uses to monitor the border. Each balloon is attached to the ground by a nylon cable that can be extended and reeled in. When in the air, the unmanned aerostats monitor the terrain below. Using radar, along with infrared and electro-optical cameras, they can "see" approximately 20 miles and pick up the movement of people and vehicles. Each blimp's radar and camera feeds are monitored 24 hours a day by Border Patrol and contractors. The aerostats are only operational 60% to 70% of the time, however, due to weather and maintenance.
Customs and Border Protection is increasingly using X-ray technology to scan for illegal drugs and smuggled immigrants that may be coming through ports of entry in vehicles. At many of these border crossings, agents have installed drive-through scanners that can detect whether a car or truck is carrying people, bundles of money, weapons or illegal drugs. Agents also have smaller machines, similar to those that luggage goes through at the airport, and portable handheld X-ray devices that can target specific areas on a vehicle. Customs and Border Protection calls this tech "nonintrusive inspection systems" and says it allows agents to investigate more vehicles faster.
In all, Customs and Border Protection says it has more than 300 drive-through scanners, 3,500 small-scale X-ray machines and 35,000 handheld devices deployed at US ports of entry. In the 2019 federal budget, CBP received an extra $520 million for additional nonintrusive inspection technology at land border ports of entry.
Originally published June 27.
Update, July 1: Adds statement from El Salvadoran President Nayib Bukele.