The LBJ hospital in American Samoa says all the travel papers for baby Michael Futi, his mother and a nurse were in order and it can see no reason why the group were held up.
Baby Michael died last week while being detained by airport authorities in Honolulu, Hawaii.
The hospital's lawyer, Terry Lovelace, says its shocked and horrified to learn Michael died while being detained.
He says Michael was referred to Honolulu as he was born with a heart defect.
Mr Lovelace says LBJ obtained a visa waiver for the boy's mother, a citizen of Samoa.
He says this is the standard procedure which the hospital has followed in many other cases.
He says someone at the Honolulu immigration really did a poor job of enforcement and this shouldn't have happened.
"They were first of the plane, first in line, the baby had an i/v in place for nutrition and had done just fine, they would have been at the hospital well before any problems would have cropped up with the child."
LBJ hospital's lawyer, Terry Lovelace.