The father of Orlando mass shooter Omar Mateen has longstanding connections to prominent Islamist groups in the U.S., a document discovered by the Investigative Project on Terrorism shows. Seddique Matin is listed as president of a then-newAmerican Muslim Alliance (AMA)chapter in Fort Pierce in a July 1997 announcement archived by the IPT.

The AMA sponsored several radical conferences in the U.S. and its leader, Agha Saeed, has spoken in defense of convicted terrorists, including Aafia Siddiqui (a.k.a “Lady al-Qaida”), Palestinian Islamic Jihad board member Sami Al-Arian, and Pakistani intelligence lobbyist Ghulam Nabi Fai.

The Fort Pierce chapter is among 10 new AMA chapters opened, the announcement in an AMA bulletin says.

AMA was incorporated as a nonprofit organization in California in 1994 “to educate the Muslim community and others on the history and laws of the United States and on affirmative participation in civic activities on a non-partisan basis.” AMA’s political activist wing, the American Muslim Political Coordinating Council (AMPCC), includes leading Islamist organizations in the U.S. including the Council on American-Islamic Relations (CAIR), the Muslim Public Affairs Council (MPAC), and the American Muslim Council (AMC).

AMA no longer exists as a registered nonprofit and it last filed tax returns in 2010. But the organization continues to maintain an activeFacebook account. In its posts, the AMA refuses to consider any Islamist motivation for the attack andlays the blame for Omar Mateen’s massacre which killed 49 people at the Pulse nightclub solely on the country’s lax gun laws.

The organization has a history of working with radical Islamist groups and has issued statements in support of several terrorists later convicted in the U.S. The FBI cut off outreach communication with CAIR, for example, after uncovering evidence placing the organization and its leaders in a U.S.-based Hamas-support network.

In October 2000, AMA co-sponsored a rally in Washington’s Lafayette Park where AMC’s then-executive director Abdurahman Alamoudi announced his support forHamas and Hizballah.

In 2004, Alamoudi was sentenced to 23 years in prison for illegal financial dealings with Libya. He also confessed to taking part in a Libyan plot to assassinate then-crown prince of Saudi Arabia.

In 2003, Saeed testified on Al-Arian’s behalf, describing the man who ran “the active arm” of Palestinian Islamic Jihad as “my friend and during the last ten years we have worked together to mainstream American politics. We have worked together to replace the culture of despair with culture of hope and the culture of bullet with the culture of ballot.” AMA’s website also featured a section entitled “Valiant Civil Rights Struggle of Dr. Sami Al Arian.”

Saeed also penned an op-ed along with CAIR’s then-national board chairman Parvez Ahmed that called for Al-Arian’s release from prison during a subsequent contempt case. The op-ed criticized U.S. counterterrorism efforts claiming “the saga of Dr. Sami Al-Arian is a repeat of past incidents in American history in which our government targeted individuals using unconstitutional and un-American tactics.”

Saeed advocated “armed resistance” at a 1999 Islamic Society of North America (ISNA) in Chicago: “United Nations has a resolution…which says… people in Palestine have the right to resist their oppression by using all means including armed resistance….” Saeed was featured as a guest speaker at Islamic Association for Palestine (IAP) conventions. Evidence unearthed in a Hamas-financing trial in Dallas, showed IAP served as a propaganda machine for the terrorist group in the U.S.

At AMA’s 7th Annual National Convention in October 2002, Agha Saeed indirectly blamed the U.S. for the 9/11 attacks. Osama bin Laden was contemptible, he said. “But I would like to say very respectfully, who brought Osama bin Laden from Saudi Arabia to Afghanistan? Who gave him million[s] of dollars? Who trained him in [the] science of war, death and destruction, deception and deceit? Who gave protection to his cause and diplomatic coverage to his enterprise? Was it not President Reagan, when he had to see mujahideen at the White House, he said, ‘When I meet you I feel as if I am in the company of the founding fathers of this country?'”

Years after working with AMA and its Islamist allies, the senior Mateen, who hosts the Durand Jirga Show from California on the YouTube channel Payam-e-Afghan, has been reported to be an ideological supporter of the Taliban. He can be seen in one video declaring his candidacy for the Afghan presidency. In another video, Mateen can be seen praising the Afghan Taliban and referring to the terrorist group as “our warrior brothers,” the Washington Post reports.

While little information is known about Seddique Mateen’s work with the AMA, the 1997 newsletter shows the Orlando shooter’s father has worked for years with some of the most visible and radical Islamists in the United States.

This article originally appeared at the Investigative Project on Terrorism.