An Argentine judge is investigating the case of two 40-year-old men who have the same first and last names, identical identity document numbers and birth certificates, all without there being any sign that one or both sets of their papers have been altered, the press reported Sunday.

Judge Eva Parcio de Seleme is trying to determine if one man tried "to steal the identity of the other," but initial studies established the authenticity of the documents of the two men, who live in the Patagonian province of Santa Cruz, the La Nacion newspaper said.

The fingerprints of one of the men, however, do not match with his identity, a fact that led police to arrest him "until it is known exactly who he might be," the federal judge said.

To uncover that, the magistrate ordered that DNA tests be performed next week to determine the identities of both men and to clarify if they are actually brothers registered separately with the same identity by their parents.

The case arose when Argentina's state pension fund and retirement administration blocked the processing of a payment to Carlos M. because he was already previously registered in the entity's files.

The man, who lives in the town of Puerto Deseado, then filed a lawsuit which, in turn, resulted in the opening of the investigation to determine who it was who had registered previously using his same identity specifications.

"We found a man who works at a petroleum service company in this city, who with a very good attitude provided his national identity document to us and took us to his house to show us his birth certificate without putting up any type of resistance," the judge told the daily.

Both men were born in Puerto Deseado in 1971, and whereas one was raised by his mother, the other was raised by his father.

The experts researching the case verified that none of the documents and birth certificates has been forged or altered, but because of the discrepancy over the fingerprints of one of the men, they are now intending to examine their DNA profiles.