Dave Caulkin/AP British police guard the area in Dover where the Dutch produce truck has been parked

The Dutch driver of the truck was detained in Dover and held on suspicion of manslaughter. On Tuesday, Dutch authorities announced the second arrest. They said they captured the suspect during a raid on three houses in the Dutch port of Rotterdam on Monday.

Police did not release the suspect's name and refused to say if the suspect was a man they had been pursuing — Dutch engineer Arie Van der Spek, 24, who owned the company that leased the truck. Police said earlier that Van der Spek registered the company, Van der Spek Transporten, on June 15. He vanished before police showed up at his Rotterdam apartment Monday.

In Dover, Dutch and British police interrogated the truck driver who brought the young immigrants, most in their 20s, on the last leg of their trip from southern China's Fujian province. And in Canterbury, the only two survivors remained under police guard Tuesday, traumatized by their futile struggle to escape the truck.

The searches in Rotterdam were carried out by a special prosecution team that deals with smuggling offences and the Southeast Asia unit of Rotterdam police. Thirty-five detectives were working on the case and three had joined British officers.

Suffocated 'One by One'

Meanwhile, the first accounts emerged from the two traumatized, dehydrated survivors — the only two to escape the truck alive late Sunday.

According to The Guardian, the survivors were taken under police guard to Kent and Canterbury hospital, 55 miles southeast of London. There, they were treated for the effects of being trapped in the truck, which had its refrigeration unit switched off as temperatures outside reached 90 degrees.

David Giles/AP Dover, where the bodies were found, is one of the busiest ports in Europe

The two survivors were understood to have been severely dehydrated and barely able to speak when discovered. A nurse at the hospital said: "They needed psychological counseling rather than treatment."

Police are aware that the lives of the survivors could be in danger from whoever was behind the smuggling racket, and provided a guard of 10 officers throughout the day.

The appalling conditions in the steel box in the summer heat attached to the truck probably meant the 58 Chinese illegal immigrants died of suffocation, a haulage expert said.

Geoff Dossitter, of the Freight Transport Association, was quoted by The Guardian as saying those who died would have suffocated "one by one" as the oxygen in the sealed container ran out.

Dossitter said: "These must have been the most horrendous deaths. You have got 60 people in the back of a vehicle and they are packed into a sealed container. The oxygen must have run out.

A Lucrative, International Racket

The stowaways in this case appeared to be from China's southern Fujian province, where racketeers known as "snakeheads" charge would-be immigrants to the West up to $60,000 for the perilous passage.

Sean Dempsey/PA/AP This April 2000 photo shows British authorities helping a stowaway jump down from the rear of a freighter truck in Dover

The disaster prompted Britain to launch a major investigation into the lucrative, international racket of smuggling immigrants to the West and focused a spotlight on the desperate measures would-be immigrants are willing to take. Authorities say crime syndicates illegally smuggle thousands of immigrants through Britain's ports.

Customs officers find up to 2,000 illegal immigrants of all nationalities hidden in trucks at or near British ports each month — and believe many more slip through. This year, Britain started imposing fines of $3,000 on truckers for every illegal immigrant found aboard and ended cash social security payments to asylum-seekers.

The hefty fine did nothing to prevent the number of Chinese illegal immigrants increasing from 225 last October to more than double that in March and April.

The British Home Office said they believe the recent increase has less to do with political persecution and more to do with the emergence of a new organized illegal trade with links to major crime syndicates.

According to The Guardian, the trade has emerged in the last five years, after governments around the world imposed fines on airlines and shipping companies that allowed passengers to travel without proper documents.

In London Tuesday, a Chinese attorney said three Chinese families living in Britain — themselves illegal immigrants — had contacted him over fears their relatives might be among the 58 victims. But they were reluctant to come forward, fearing deportation. The lawyer called on the British Home Secretary to offer an amnesty to anyone wanting to give information about relatives they were expecting to join them in Britain.

In Beijing, the Foreign Ministry did not confirm that the stowaways were Chinese but said it was shocked and was in contact with British authorities.

"The international community has the responsibility to join hands to crack down on illegal immigration," a ministry spokesman said.

— The Associated Press and Reuters contributed to this report