David Hemler stepped forward two weeks ago and revealed his identity to a local newspaper. He said he had deserted from a U.S. air force base in Germany in 1984 aged 21 and hitchhiked to Sweden where he lived under an assumed identity.

The 49-year-old, twice married with three children in Sweden, said he came forward because he wanted to see his parents in the United States and wanted his children to see their grandparents.

Two officials from the U.S. air force base in Ramstein, Germany, including a crime investigator, have arrived in Sweden and on Thursday met Hemler's lawyer Emma Persson along with an official from the U.S. embassy, Persson told Reuters.

"They want to do a DNA test and take fingerprints to check his identity. He is ready to do that because he wants to show that he is who he says he is," she said.

"They want him to hand himself over and go to court," she said, adding Hemler had not agreed to that. "They were clear that there would be some sort of punishment."

Hemler was quoted by newspaper Dagens Nyheter on Friday as saying he wanted guarantees on the maximum punishment.

"For the sake of my wife, my children and my parents I cannot risk being in jail for a long time," he said.

He said he did not feel that he should suffer any penalty for deserting as the 28 years of separation from his family was punishment enough.

The U.S. Air Force Office of Special Investigations has Hemler listed as one its eight most wanted fugitives on its website.

Hemler said he deserted after getting involved with a pacifist church and becoming disillusioned with the policies of former U.S. President Ronald Reagan.

He hitchhiked via Denmark to Sweden where he settled down under an assumed name, revealing his true identity to no one.

He told Sweden's TV4 that he had visited Sweden twice before deserting and sympathised with the politics of then Prime Minister Olof Palme, who was opposed to falling under the influence of the United States or former Soviet Union.

Hemler's brother has told U.S. media that the family accepts that Hemler is genuine and is happy he has returned.