* Oscar and Valeria Martinez died trying to cross Rio Grande * Aid worker says Trump chaos killing innocent migrantsOscar Martinez’s body on its way back to El Salvador. Photograph: Carlos Jasso/ReutersThe bodies of a young father and his tiny daughter who drowned in the Rio Grande have been repatriated to their native El Salvador, two days after shocking images of their deathly embrace galvanized debate over America’s migration crisis .Wrapped in white body bags, Óscar Martínez, 26, and Valeria, 23 months, were transported first by road then by air, accompanied by Martínez’s bereaved wife Vanessa Ávalos, 21, who had been standing helplessly on the riverbank of the river when her loved ones were swept away by the current.As the bodies made their sombre journey on Thursday, a veteran US humanitarian worker who runs a shelter in the Mexican town of Matamoros, where they died, accused Donald Trump of causing chaos at the US-Mexico border and said innocent migrants are dying as a result.Larry Cox, the founding director of the Casa Bugambilia shelter in Matamoros, spoke out about the terrible dangers migrants face and blamed Trump for stoking fears of foreigners in the US and failing to cope with an increase in families crossing the border.The Trump administration has severely restricted people from claiming asylum and is detaining those who cross the border unlawfully, while trying to push through a policy of making migrants wait in Mexico as their legal cases are processed.Cox said: “There is nothing I could say to President Trump that would bring meaning to this crisis. I believe the people in this administration have made up their minds about what they are going to do with asylum.”Martínez, 26, and his daughter, who had journeyed from El Salvador, died together in the river that divides Mexico from Texas after being unable to apply for asylum at the US port of entry, as was their right under international law.Cox criticized the immigration crackdown but also said federal agencies such as border patrol and immigration enforcement “need somebody in charge who knows how to deal with the migrant surge. The president is not that person.”Cox established the Casa Bugambilia shelter with his wife, a doctor, in 2004 after years of volunteering in Matamoros, across the border from Brownsville, Texas. Initially the pair started the shelter for people in the town who needed basic medical services.But Cox said he decided to open the shelter to migrants last October when he saw how they were blocked at the international bridges by the practice known as “metering” – strict limits that force long delays on those waiting to be interviewed while claiming asylum.Cox said: “You can make it really tough and dangerous for asylum seekers to try to get to the US, but if the danger level is higher at home in Central America they are not going to be discouraged from crossing [the border]. The solution lies in helping these countries provide better living conditions for their citizens.”Cox is currently receiving medical attention in the US, worn out from months of being overwhelmed trying to help stricken families passing through Matamoros.The 69-year-old told the Guardian he worries about the migrants back at his shelter while he’s away, and about the viability of the shelter.“We are a non-profit that now serves asylum seekers,” he said.He calculated that the shelter has saved US taxpayers over $1m, doing a desperate job that the US government won’t act to prevent or deal with itself.“That to me is insane,” he said. He added: “We are housing people at our expense and that is making Trump happy.”He said he was extremely upset to hear about the deaths of Oscar Martinez and Valeria – two of dozens of migrants who have drowned in the Rio Grande this year.