BUENOS AIRES, Argentina (AP)--The discovery of a 51st victim Friday two days after Argentina's deadliest train wreck in decades left the man's family devastated and prompted rock-throwing and other violence by protesters holding vigil at the scene.

The search for 20-year-old Lucas Menghini Rey, whose body was missed in the chaotic response to Wednesday's crash, brought a sharp focus to widespread anger over the crash, which also injured 703 of the 1,500 people on the packed train.

Family and friends collapsed together at the news, while others keeping vigil at the station erupted in anger. Some shouted ``throw them all out, not one should remain!'' The phrase became iconic during the protests of a decade ago, when public outrage over a failed economy forced a series of presidents to resign.

Riot police responded with tear gas and batons, clearing the station and making arrests. At least one officer was bloodied, and dozens of youths threw objects at passing buses and taxis. Some started small fires and destroyed property as Menghini Rey's family and friends left in tears.

While the cause remains under investigation and the motorman who failed to stop in time has yet to make a statement, many commuters are furious that President Cristina Fernandez's government has apparently ignored repeated warnings about inoperable or missing brake equipment and other safety threats.

Many suspect corruption and mismanagement contributed to the crash, which also injured 703 of the 1,500 passengers when the eight-car train slammed into the end of the line at less than 12 mph (20 kph).

Menghini Rey hadn't appeared on any lists of dead or injured, about 30 of whom remain hospitalized, and city officials announced Friday that all other passengers had been accounted for. His body was found after Security Minister Nilda Garre personally took over and ordered police back to the wreck, searching ``even in the most impossible places,'' Telam reported.

Inside the station, his family and friends stacked boxes plastered with his picture and numbers to call, along with the phrase ``we are as fragile as cardboard,'' a feeling shared by many after seeing how the massive train cars crumpled and crushed hundreds of passengers inside.

Menghini Rey's family hadn't seen him since he said goodbye early that morning to his 3-year-old daughter, promising to bring her a toy when he came back from work at a downtown call center, his friend Fernando Diaz told The Associated Press.

But rumors flew that he had survived. One city official even said he had been seen by psychiatrists at a hospital who released him into the streets, and that he might have been suffering from shock and post-traumatic stress.

Argentina's third deadly train accident in less than a year has focused attention on the dilapidated passenger rail system, privatized in 1995 and heavily subsidized by the government since then to keep ticket prices low.

Hard stops are common around the world, rail experts say, so modern cars are designed to avoid the crumpling that can happen when the lead car hits a barrier. But these cars were built decades ago and bought as refurbished castoffs from other urban rail systems.

While a shock-absorbing bumper at the end of the line kept the front of the train intact, the cars behind it slammed into each other, shoving the second car, with hundreds of people standing inside, deeply into the first. Rescuers had to use Vaseline and cooking oil to untangle the living and dead.

Argentina boasted the continent's most modern trains in the early 20th century, but they were in decline for decades before the system was privatized in the 1990s by President Carlos Menem, who promised much better service.

The family-run Trains of Buenos Aires company got the concession that includes the Sarmiento line. Repeated audits since then determined that the TBA hasn't fulfilled its contract.

The tragedy ``is a direct consequence of the failure to comply with basic standards'' that were identified in a 2008 report by the nation's Auditor General, said the watchdog office's chief, Leandro Despouy.

That report details multiple problems with brake systems: missing emergency brake levers and inoperable hand brakes and brake cylinders. It was presented that year to the presidency and the congress. No one did anything, complained Despouy, whose main political support comes from a minority party, the Radical Civic Union.

Company officials countered after the crash that their trains are safe, and suggested human error was to blame.

Meanwhile, justice has moved slowly in the case of Ricardo Jaime, who resigned as transportation minister after Argentine media revealed that he had accepted free flights to Brazilian vacations from TBA executives while deciding how much the company would get in government subsidies. He remains outside of jail while awaiting trial on bribery charges.

``Here the blame is shared between the company and the government that fails to control it,'' said Andres Peralta, a 28-year-old student who signed a leftist group's petition to re-nationalize the trains.

The government said won't decide on the TBA's future until the courts take action.

Fernandez has been silent since the tragedy, and her ministers have declined to take questions at news conferences on the government response. She left the capital Friday for her home in Calafate, in Argentina's remote Patagonia region. The President of Paraguay, Fernando Lugo, planned to see her there after meeting with survivors from his country.

The president's absence became another sore point on social networks. One Argentine's Twitter message, frequently re-tweeted, said ``Mrs. President of the Nation, Cristina Fernandez de Kirchner, please, come back to Buenos Aires: show that it hurts you as it does us.''

Another compared her to Chile's president: Sebastian ``Pinera was there until they rescued the last miner. CFK left to Calafate.''