Frank Izaguirre’s boots press into the mud as he climbs aboard a small patrol boat in the Rio Grande. Staring across a narrow channel towards Mexico, the US Border Patrol special operations supervisor appears far more calm than the choppy waters ahead of him – but tensions are clearly high for his team of agents, who are embarking on their daily game of cat and mouse.

“It’s a bad day for anyone trying to make it to America,” he says.

An unusually active hurricane season has brought storm surges and heavy rains to Texas in mid-October, making the stretch of water snaking between Mexico and the United States an even more treacherous obstacle for those attempting to cross the border.

Meanwhile, drug trafficking and illegal immigration has experienced a resurgence in the region, officials tell The Independent, after the federal government’s deterrent strategies appeared to cause a dip in illicit activity earlier in the year.

“It’s business as usual around these parts,” a border patrol agent says into his headset while steering the boat through heavy currents. “We’ve got to protect America 24/7.”

For the men and women who patrol Laredo, a gateway city to Mexico nearly 70 miles south of San Antonio, some anxiety about what’s to come during their Monday morning boat ride may be warranted. Over the weekend agents found four bodies believed to have been migrants who drowned while swimming to the US side of the riverine, in an area considered to be a hotspot for illegal immigration.

Abandoned belongings can be seen floating along riverbanks under the Juárez-Lincoln International Bridge, one of the nation’s most active ports of entry; a deflated truck tire hangs from a dirt slope; empty water bottles litter the riverbeds near worn pathways; a soiled piece of clothing hangs from a thick branch.

Altogether, these relics provide evidence for thousands of untold journeys – some of which are successful, and others that end right here between both nations’ shorelines.

The Independent goes on a ride-along with US Border Patrol Show all 15 1 /15 The Independent goes on a ride-along with US Border Patrol The Independent goes on a ride-along with US Border Patrol Texas and Mexico are connected by entry points like these. US Border Patrol in Laredo, Texas conducts daily patrols throughout the Rio Grande, snaking between the US and Mexico, where it searches for migrants and drug traffickers. The legal entry point to Mexico can be seen above the riverines frequently used by cartels to funnel narcotics into the US. Chris Riotta The Independent goes on a ride-along with US Border Patrol US Customs and Border Protection oversees its side of the entry point. US Customs and Border Protection officers oversee the processing of nearly two million trucks and three million pedestrians annually at the Laredo sector, which also processes the majority of trade between the US and Mexico. Chris Riotta The Independent goes on a ride-along with US Border Patrol The Rio Grande snakes between Mexico and the United States. The US and Mexico have bordering coastlines in Laredo Texas, where the Rio Grande's occasionally rough currents splash onto both nations' shores. For migrants attempting to enter into either country, the swim is much more dangerous than it appears. Chris Riotta The Independent goes on a ride-along with US Border Patrol Drug traffickers and migrants use "highways" to cross the border. US Border Patrol agents call worn pathways like these "highways," as they are frequently used by drug traffickers and migrants entering into the US. Chris Riotta The Independent goes on a ride-along with US Border Patrol The journey is still far from over. If they're able to make it onto land, many obstacles still remain for migrants and drug traffickers. US Border Patrol agents are equipped with high-tech security, K-9 units and aerial camera footage surveilling 40 miles of borderlands. Chris Riotta The Independent goes on a ride-along with US Border Patrol Border Patrol uses classic methods and high-tech to surveil the border. A control room at the Laredo sector headquarters is fully-manned 24/7 with a team of local employees who alert agents on the ground of border crossings in real-time. Their cameras live-stream 40 miles of the 170 mile territory the sector covers. Chris Riotta The Independent goes on a ride-along with US Border Patrol The US provides trusted traveler programs on both its southern and northern borders. Officers lead the way to Sentri offices, which runs a trusted traveller program from US and Mexican local residents who regularly cross the border for work or leisure purposes. Chris Riotta The Independent goes on a ride-along with US Border Patrol The pathway to freedom. Once travellers are processed, they walk up this ramp towards the US. Many Mexicans cross the border each day with collapsable shopping carts to buy goods while visiting the country. Chris Riotta The Independent goes on a ride-along with US Border Patrol But first, the wait. A dog waits for their owner to go through processing with US Customs and Border Patrol. On a good day, processing can take under an hour. On a bad day, well, there's just no telling how long one might be stuck inside the Laredo sector field offices. Chris Riotta The Independent goes on a ride-along with US Border Patrol The first lady of CBP. Inside the Laredo field offices, US Border Patrol agents keep a framed photo of Christine Davis, the first female agent to join the federal agency in 1975. Chris Riotta The Independent goes on a ride-along with US Border Patrol "The hall of fame." US Border Patrol also honors those who have served in the agency for over thirty years. Chris Riotta The Independent goes on a ride-along with US Border Patrol Officers inspect a vehicle in secondary processing. Outside, officers are conducting secondary inspection on a vehicle that's been pulled aside for further investigating. Chris Riotta The Independent goes on a ride-along with US Border Patrol The waiting room for detained migrants. A US Customs and Border Protection officer shows the inside of a holding room where people requiring further questioning go through secondary processing. Chris Riotta The Independent goes on a ride-along with US Border Patrol A man and his daughter go through processing. US Customs and Border Protection also regularly provides humanitarian visas and other temporary permissions for people with valid reasons seeking entry to the US. Here, a father and his daughter await to see whether they will be provided one of those visas. Chris Riotta The Independent goes on a ride-along with US Border Patrol Laredo processes over three million pedestrians annually. Thousands of legal asylum seekers, migrants and refugees seek entry to the US through the southern border annually, where they go through processing at offices like this after arriving at a legal port of entry. For many, the trip can take days, if not weeks or even months. Chris Riotta

As Donald Trump tweets warnings about a migrant caravan heading towards the US full of “criminals”, the fact remains the vast majority of those migrants will likely end their journeys before reaching the US border, as has happened several times during the course of the 15-year seasonal tradition. Those that do decide to cross the border often do so in compliance with US laws in order to seek asylum, which requires physical entry into the country before a person can be considered for the protected status.

Officials along the border are far more concerned about the stories of migrants that go unreported each day, however. Failing to save those four lives are far more likely to keep these agents awake at night than nightmares of a supposed migrant “army”.

“When President Trump came into office, [migrants] asked themselves, ‘What is he going to do, what does this mean for us, how serious is this?’” US Border Patrol agent Barrera says. “Now they’re ready to take that risk again.”

Just above the waterway, US Customs and Border Protection (CBP) processes more than two million trucks and three million pedestrians entering the US annually at the port of Laredo – although there were no migrant arrests during The Independent’s ride-along.

Advancements in both border security technology and processing efficiency have allowed the city and its suburbs to develop into a major trade hub, while stopping an unprecedented level of drug smuggling and illegal immigration in its tracks.

The sector is one of the federal agency’s largest, with nearly 3,000 employees working at eight different ports of entry, all of whom are collectively tasked with funnelling the majority of trade between the US and Mexico.

“It’s a natural corridor for trade, both legitimate and illegitimate,” says Rick Pauza, a CBP public affairs officer, while touring the Laredo field offices. “We seized about 156,000 pounds of narcotics within the fiscal year 2017 – worth over $200m – and about 49,000 persons were deemed to be inadmissible for entry.”

The region’s continued growth relies on trust between the CBP, US Border Patrol agents and their surrounding – largely immigrant – communities, however, where the agency is suffering an identity crisis that has been exacerbated by the current White House administration. In order to move forward with support from the city of Laredo, the predominant investor in recent renovations to the sector headquarters and ports of entry, the agency’s local leadership will first have to face some ugly truths.

President Donald Trump’s zero tolerance policy implemented in late May earlier this year led to the separation of families legally seeking asylum in the US, before the president walked back the guidelines in an executive order weeks later. The policy, which means all adults entering the US illegally are prosecuted, sparked nationwide protests and outcry over the treatment of refugees and legal migrants arriving at the nation’s ports of entry.

In numerous statements to The Independent, border patrol agents and CBP officers at the Laredo sector say they did not follow certain components of the policy, including guidelines to separate migrant families upon their detainment.

When asked for further information on how the federal policy impacted operations in Laredo, a border patrol public affairs officer added that families remained together at all times through processing, and that the sector continued to follow Obama-era guidelines during its implementation, prioritising cases of migrants with criminal backgrounds for deportation rather than grouping all cases together, as the policy had ordered.

RAICES, a Texas-based group working to reunite families separated by the zero tolerance policy, tells a different story. A spokesperson for the group immediately identified at least 12 cases of family separations at Laredo’s entry points from the period in which the policy was in full effect, including three cases in which the separated children were under the age of 10. They noted there could potentially be “some integrity issues” in that data, however, which comes directly from forms filled out by over 2,000 migrants who arrived at bus stations across the state after being processed by CBP.

“In a lot of these cases of separations we heard that parents were terrified while going through processing since they were not informed about their children’s whereabouts,” Nate Roter, who works for the immigrants’ rights group, tells The Independent.

Citing privacy concerns, CBP officials at the Laredo sector declined to provide a comment responding to the discrepancy or clarifying their stance on the zero tolerance policy. However, after several exchanges, they later admit family separations may have occurred across their ports of entry under the original guidelines. The White House did not respond to requests for comment.

Still, CBP has managed to push forward with expansion goals in the region by avoiding national politics and focusing on the communities it serves. The Laredo sector is the first in the agency to launch a smartphone app which provides updates and press releases about the rescues, drug seizures and human smuggling attempts it intercepts on a daily basis.

A partnership that began in 2015 allows officials from the US and Mexico to work side-by-side at Laredo’s ports, sharing intelligence and inspecting vehicles and commodities for apparent anomalies at an increasingly rapid scale. Using X-ray scanning technology, CBP officer Luera observes a truck carrying nearly a dozen gas tanks filled with narcotics, as agriculture specialists sift through boxes of fresh broccoli in a chilled room. If produce contaminated with microbial pests goes unnoticed, the potential devastation could amount to hundreds of billions of dollars in losses for US farmers.

Over the years, officials at the federal agency have combined technological breakthroughs with practices like community policing in order to surveil the nearly 170-mile region. A control room at the sector headquarters is fully manned around the clock by plainclothes employees, featuring a wall of flatscreen TVs that show 40 miles of real-time aerial footage from the border. Those CBP employees – the vast majority of whom live in Laredo and its surrounding areas – are able to communicate directly with agents on the ground to alert them of nearby border crossings.

“It helps if they live here so they can provide a real sense of what they’re seeing and where they’re seeing it happen,” agent Barrera says. “At the end of the day, we’re all just doing our jobs, like cops and doctors.”

But officials say high-tech security and sprawling border fencing – a portion of which the Army Corps of Engineers built to surround Laredo Community College decades ago, in an attempt to prevent migrants entering through the Rio Grande from running into the parking lot and blending in with students – can only go so far.

When asked about Mr Trump’s plans to build a wall stretching the entirety of the border, Mr Izaguirre is prepared with a response. “Nothing can replace boots on the ground,” he says. However, he suggests a sprawling wall could in fact help reduce migrant deaths along the border – so long as the wall includes a hiring expansion for the nation’s largest federal law enforcement agency.

“It’s not the final solution but it could be helpful, especially if we’re able to properly monitor it,” he says. “If we can limit the entry points where folks are able to cross over, we may be able to get to them quicker for rescues than without it.”

Wall or not, Mr Izaguirre says the scores of CBP agents who provide America’s first, and sometimes last, defence against countless sources of harm will continue carrying out the mission of the agency.