Omar Mateen’s father, Seddique, says he last saw his son a day before the Orlando nightclub shooting. And nothing seemed amiss. (Lee Powell/The Washington Post)

The father of the Orlando nightclub gunman insists that his son was not motivated by Islamist radical ideology, describing the 29-year-old as a “a good son” who did not appear agitated or angry the day before the deadliest mass shooting in U.S. history.

In two videos — one is an interview with The Washington Post in Florida, and the other is a separate posting to Facebook — Seddique Mateen offered no hints on what could have driven his son, Omar Mateen, to carry out the carnage early Sunday before police killed him.

During the rampage, Mateen pledged loyalty to the Islamic State in a call to 911, but his father said he did not believe it was a genuine pledge of support.

“I think he just wanted to boast of himself,” the elder Mateen told The Post late Sunday in an interview from his home in Port St. Lucie, Fla. “No radicalism, no. He doesn’t have a beard even. . . . I don’t think religion or Islam had anything to do with this.”

Seddique Mateen said his son stopped by the day before the rampage and showed no apparent warning signs.

“He was well behaved. His appearance was perfect,” he said. “I didn’t see any sign of worrying or being upset or nervous.”

The elder Mateen said he planned to travel to Orlando and visit those who were injured or lost loved ones in the shooting at a nightclub popular with the city’s gay community.

“If they’re not ready, I still say to them, ‘I’m sorry,’ ” he said. “I’m saddened for their injury or if they lost their dear one.”

But in a Facebook video posted early Monday, he said, “God himself will punish those involved in homosexuality.”

He had a child and a wife and was very dignified, meaning he had respect for his parents,” Seddique Mateen wrote, standing in front of the flag of his apparent birthplace, Afghanistan. “I don’t know what caused him to shoot last night.”

Seddique Mateen said his son had access to a pistol through his employer. The Post and other media outlets reported Sunday that Omar Mateen worked as a security guard for G4S, a global security and contracting company.

“I am deeply saddened and announce this to the people of America,” said Seddique Mateen in his Facebook video, noting his son carried out the attack during the Islamic holy month of Ramadan.

Seddique Mateen, speaking in Dari, concluded the video by expressing disbelief that his son took it upon himself to seek retribution against the LGBT community.

“God himself will punish those involved in homosexuality,” he said. “This is not for the servants” of God.

In Afghanistan, officials were still trying to piece together the family’s background.

Afghan government officials said they did not know when Seddique Mateen left the country but noted millions of Afghans fled after it was invaded by the former Soviet Union in 1979.

Omar Mateen, 29, was born in New York but moved with his family to Florida as a child.

But Seddique Mateen appeared to maintain a strong affiliation to Afghanistan, hosting a television show broadcast from California that weighed in on the country’s political affairs.

He also filmed dozens of sparsely viewed, rambling YouTube videos portraying himself as an important Afghan analyst and leader.

In one video, the elder Mateen expresses gratitude toward the Afghan Taliban while denouncing the Pakistani government.

“Our brothers in Waziristan, our warrior brothers in [the] Taliban movement and national Afghan Taliban are rising up,” he said. “Inshallah, the Durand Line issue will be solved soon.”

The “Durand Line issue” is a historically significant one, particularly for members of the Pashtun ethnic group, whose homeland straddles the border between Afghanistan and Pakistan. The Durand Line is that border. It is not clear whether the Mateens are Pashtun. The Afghan Taliban is mostly made up of Pashtuns.

The line was drawn as a demarcation of British and Afghan spheres of influence in 1893. The British controlled most of subcontinental Asia at the time, though some parts, including what is now Afghanistan and northwest Pakistan, were only loosely held.

The line was inherited as a border by Pakistan after its independence. Because it splits the Pashtun population politically, it is seen as a cause for their marginalization. Pashtuns are the largest ethnic group in most of eastern Afghanistan and northern Pakistan.

Just hours before the shooting in Orlando, Seddique Mateen posted a video on a Facebook page called “Provisional Government of Afghanistan — Seddique Mateen.” In it, he seems to be pretending to be Afghanistan’s president, and he orders the arrest of an array of Afghan political figures.

“I order national army, national police and intelligence department to immediately imprison Karzai, Ashraf Ghani, Zalmay Khalilzad, Atmar and Sayyaf. They are against our countrymen and against our homeland,” he says, while dressed in army fatigues.

The most recent video on Mateen’s YouTube channel shows him declaring his candidacy for the Afghan presidency. The timing of the video is strange, as it came a year after presidential elections were held in Afghanistan.

Mateen appears incoherent at times in the video, and he jumps abruptly from topic to topic. His use of Dari, instead of Pashto, the language of Pashtuns, was another strange element of his presentation, given that he is discussing issues of Pashtun nationalism.

“People would make jokes of this guy, especially after videos surfaced of him claiming to be the president in exile,” said one senior Afghan government official, who asked not to be identified because he was not authorized to speak to media. “He looked very serious, but no one could tell what he was talking about.”

Seddique Mateen also appeared to go to extraordinary lengths to appear as if he was a relevant figure in Afghan politics.

In 2014, for example, Seddique Mateen uploaded a video to YouTube that showed him interviewing Ghani. At the time, Ghani was a candidate in Afghanistan’s most recent presidential election.

Ghani initially had no recollection of meeting the elder Mateen. After scrutinizing the video on Monday, his staff determined Seddique Mateen had interviewed Ghani during his unsuccessful bid for president in 2009.

tim.craig@washpost.com

Bearak reported from Washington, and Powell reported from Port St. Lucie, Fla. Sayed Salahuddin and Mohammad Sharf in Kabul contributed to this report.