The transfer to his Afghanistan-born brother in law also lists Mateen's wife as a witness.

Several weeks before he massacred 49 at an Orlando gay nightclub, Muslim terrorist Omar Seddique Mateen transferred over his interest in his Florida home to his older sister and Afghan brother-in-law, property records show — an indication the family possibly had some knowledge of his martyrdom plans.

Authorities say the fatally shot Mateen clearly was prepared to die in a gun battle with police during the June 12 attack, the deadliest act of terrorism on U.S. soil since 9/11.

On April 5, Mateen “quit-claimed” the deed on his Port St. Lucie, Fla., house, signing it over to his sister, Sabrina Abasin, and his brother-in-law Mustafa Abasin according to county property records. The records list his wife Noor Salman as a witness in the curious real estate transaction.

Mateen’s wife, who is expected to be charged as an accessory in her husband’s attack, reportedly has told authorities Mateen began casing targets as early as April. He was regularly training with firearms well before April.

Earlier this week, the mysterious brother-in-law — Mustafa Abasin, aka Mustafa Aurakzai — escorted the widowed Salman, who wore a hoodie to shield her face from cameras, to the Port St. Lucie home to collect belongings. Florida state records indicate he was born in Afghanistan.

The 43-year-old Abasin has been questioned by federal investigators. In fact, the entire family is under investigation. FBI agents have expanded the investigation overseas to include family connections in Afghanistan.

Abasin is listed on state articles of incorporation papers as a founding director of a pro-Taliban nonprofit group set up by Mateen’s father, Seddique Mir Mateen. Abasin’s wife, Sabrina Seddique Abasin, also sits on its board.

An Afghan immigrant, the senior Mateen founded the The Durand Jirga Inc. in 2010 to support the Taliban and the tribal region it controls along the Afghan-Pakistani border.

In a recent video posted on the Web, Mateen expresses gratitude toward the Afghan Taliban, who stone homosexuals to death and launch terrorist attacks on U.S. soldiers, calling them “our warrior brothers.” He has criticized U.S. actions in Afghanistan, and complained about American and other Western “foreigners” in his home country.

Abasin, also active in Afghan politics, has echoed that criticism.

In a paper he recently posted in Farsi, Abasin criticizes Afghans who have adopted American culture, according to an English translation by CounterJihad.com. He also rails against tribal chiefs who do not speak out against democracy in Afghanistan.

In recent social media posts, Abasin blames guns for his brother-in-law’s shooting, calls presumptive GOP presidential candidate Donald Trump a “racist” for wanting to restrict Muslim immigration, and says he’s involved with working with “refugee camps.” It’s not clear if the refugees include the displaced Syrian nationals the Obama administration is resettling in U.S. cities.

Abasin’s occupation is listed as health insurance broker, while his wife Sabrina is listed as a cosmetologist. A Facebook page lists Abasin as an “independent broker” with Allianze, and a member of the Association of Pakistani-Americans of Central Florida and the Iranian Cultural Society of Greater Miami-ICS.

Neither he nor his wife responded to requests for comment.

Sabrina, like her late brother Omar Mateen, is a registered Democrat. Federal campaign records show their father gave money to the Democratic Congressional Campaign Committee last year.

Abasin appears to be obsessed with AIDS.

Earlier this year, he searched and downloaded an article, “How to prevent the transmission of HIV AIDS virus,” and just days before his brother-in-law attacked the gay club in Orlando, he tweeted out a complaint about CNN’s series about the 1980’s decade, arguing it focuses too much on AIDS and the gay community.

“Eighties is an interesting TV show, @tomhanks is executive of the TV show, but why did he speak about AIDS? It was out of the topic,” he wrote on June 9.