A photograph of one of the Boston bombing suspects has emerged showing him standing close to a family devastated by the blast.
Dzhokhar A Tsarnaev, 19, is believed to be the man in the photograph.
Standing close to him are the Richard family; eight-year-old Martin Richard was killed in the blast , his mother suffered brain injuries, and his sister lost a leg.
The other suspect, believed to be his brother, is named Tamerlan.
It has been reported that they are from Chechnya or Dagestan and have lived in the US for at least one year.
The father of the suspects, speaking from the Dagestan capital of Makhachkala, called Dzhokhar "a true angel".
He added: "He is a second-year medical student in the U.S. He is such an intelligent boy. We expected him to come on holidays here."
Sky's Moscow correspondent Katie Stallard said the Dagestan region is associated with insurgents.
"On (a social networking page) he describes himself as having studied in Makhachkala, that’s the capital of Dagestan, and that's very much at the heart of the regional insurgency at the moment.
"It used to be that it was Chechnya that was the heart of this insurgency, but a crackdown has forced much of that insurgency into neighbouring regions."
Earlier, the FBI and Boston police released new pictures of the two suspects, who investigators had described as "armed and dangerous".
The images released on Friday morning show one suspect wearing dark clothes, a dark cap and sunglasses.
He is understood to have been shot dead.
The second suspect is seen wearing a white baseball cap, which is reversed allowing a clearer view of his face.
Police took him into custody overnight.
CCTV footage was released of the pair on Thursday, in which they are seen carrying bulky backpacks as they walk the route of Monday's race in the heart of the city.
The men were filmed heading in the direction of the finishing line, moments before both bombs went off seconds apart.
Three people were killed and more than 180 others injured in the explosions.
The bombs were crudely made with explosives, nails and ball bearings packed into pressure cookers, investigators close to the case have said.