Rio Grande drowning: 'I knew it was the last time I would see my son'

Óscar Alberto Martínez Ramírez, 25, and his daughter Valeria drowned on Sunday while trying to cross from Matamoros, in the northern Mexican state of Tamaulipas, into Texas.

His mother, Rosa Ramírez, told the BBC how she felt when her son and his young daughter set out on a journey from which they would never return.