Omar Al Bayoumi has been a subject of the theories of the alleged Saudi Arabian government link to 9/11. In the video provided by 9/11 Families United, Bayoumi is seen at the U.S. Capitol, which the families say is him “casing” the building.(Credit: 9/11 Families United via NewsNation)

(NewsNation) — A new letter shows the U.S. government siding with Saudi Arabia and objecting to the unsealing of evidence related to the 9/11 attacks.

Families of those who died on 9/11 have filed a lawsuit seeking to release evidence they say shows the Saudi government was complicit in the attacks. Fifteen of the 19 hijackers involved in 9/11 were Saudi, and al-Qaida leader Osama bin Laden also had ties to the Saudi royal family. However, the country has denied any involvement in the attack that killed nearly 3,000 people.

The Department of Justice and FBI sent a letter to the judge overseeing the lawsuit between 9/11 victims and Saudi Arabia, asking him not to unseal the material the families are pushing to make public.