Lawyer Ed Escueta said the embassy committed a "grave injustice" when it failed to put his clients travel documents in order before he left for the US last Dec. 26.
As a result, the US Immigration and Naturalization Service (INS) issued a "detainer" against Jimenez on the assumption that he was extradited, Escueta said.
The detainer seeks to hold Jimenez in jail even though his lawyers in Florida had convinced the court to allow him to post bail on certain conditions.
The INS declared Jimenez an illegal alien on the premise that he had been extradited and for his purported lack of documents.
"US Embassy officials in Manila can easily shoot down the two arguments cited by the INS in seeking to indefinitely incarcerate my client," Escueta said in a statement.
"For one, they were privy to the voluntary nature of Representative Jimenezs trip, and were also directly responsible for ensuring that all the travel documents my client would need were met."
Escueta said the extradition case against Jimenez became moot and academic when he volunteered to return to the US to face charges of making illegal campaign contributions to Democratic Party candidates, reportedly including former US President Bill Clinton.
"Documents do not lie. Its just a matter for the US Embassy standing by its original position that Jimenez was not an extraditee to start with. Its also incumbent upon the US Embassy here to rectify the error on my clients supposed lack of travel documents," he said.
Escueta blamed US Embassy legal attaché James Nixon for allegedly not ensuring that Jimenezs papers were in order, adding that Nixon even lost his clients passport.
Jimenez is hopeful that his colleagues in the House of Representatives will see to it that all the necessary documents can be made available to inform the INS that Jimenez is not an illegal alien.