A Guantanamo detainee who was to be freed must now remain in jail after a federal appeals court ruled there is enough evidence linking him to al-Qaida.

The judges Friday overturned an earlier decision freeing Hussain Salem Mohammad Almerfedi, saying the lower court had not “given sufficient weight” to the “reliable evidence.”

The judges said the U.S. government did not need to prove Almerfedi's guilt “beyond a reasonable doubt” as is the standard in a U.S. criminal trial. The ruling stated that the government could detain Almerfedi as long as the evidence was “more likely true than not true.”

The court documents say Almerfedi claims he was trying to emigrate to Europe for a better life.

But the U.S. government alleges Almerfedi was actually working for al-Qaida. The government says the Yemeni national admits that he spent a month-and-a-half in Pakistan at the headquarters of an Islamic missionary organization designated by the U.S. as a terrorist support entity.

The government also argued Almerfedi's supposed route to Europe brought him closer to Afghanistan's border than to any European country.

The government says Almerfedi was arrested with $2,000 in cash he cannot explain. And it cited testimony from a fellow Guantanamo detainee saying Almerfedi stayed at an al-Qaida-linked guesthouse in Tehran.

Almderfedi's lawyer argued the fellow detainee's testimony was not reliable, since it cited dates that were after Almerfedi was already in custody. And he argued Almerfedi's inexperience with international travel and his reliance on help from people he met along the way explained the rest of the evidence.

Almerfedi was arrested by Iranian authorities sometime after the terrorist attacks on September 11, 2001. He was turned over to Afghan authorities in 2002, and transferred to the Guantanamo Bay detention center in May 2003.