The Muslim terrorist who killed at least 49 people in an Orlando nightclub early Sunday was an angry loner who beat his ex-wife, alienated co-workers and made at least two mysterious trips to Saudi Arabia, according to people who knew him and law enforcement authorities who are now piecing together his descent into radical Islam.

One avenue of investigation is a pair of trips Omar Mateen, 29, took to Saudi Arabia in March 2011 and March 2012 for umrah, a non-mandatory visit to Mecca for Muslims, Saudi Arabia Interior Ministry spokesman Maj. Gen. Mansour al-Turki told The Associated Press in a text message Monday. Umrah can be performed at any time of the year.

Law enforcement officials could not confirm to Fox News what Mateen’s exact itinerary was, including cities he visited or individuals he may have met with; however, Mateen is known to have stayed in the Kingdom for 10 days during the first trip and eight days during the second trip.

“We obviously don't know the details yet, but it's worth recalling how the San Beardino shooters met in Saudi Arabia and were engaged there,” Ryan Mauro, a national security analyst for the Clarion Project, told FoxNews.com, referencing the ISIS-inspired December terror attack that killed 14 people in Califoia. “These trips to Saudi Arabia also make it less likely that Mateen is a so-called ‘lone wolf’ who acted mostly independently.”

The Middle East jaunts came before Mateen was the subject of two FBI terror investigations. He was interviewed by the bureau twice in 2013 and once in 2014, but, officials said Sunday, Mateen was not assessed to be a threat. At the time of the shooting, Mateen was not under surveillance or the subject of an investigation, authorities said.

Mateen appeared first on FBI radar in 2013 after co-workers at G4S Security reported that Mateen made “wild” claims that he had family and friends in Al Qaeda and Hezbollah and was coected to the Boston Marathon bombers, The Washington Post reported. In a 911 call Mateen made during the Sunday moing attack, in which he also pledged allegiance to ISIS, Mateen reportedly mentioned the marathon bombers again.

The 2013 investigation was closed after agents came to believe the statements were mere boasts and Mateen was not legitimately tied to any terror groups.

“He seems to be looking for any opportunity to associate with the terrorist group du jour,” a senior U.S. official told The Washington Post.

President Obama said Monday it appears Mateen was inspired by extremist information disseminated over the Inteet and said the FBI followed proper procedure when they interviewed him previously.

FBI agents were back at Mateen’s door in 2014, this time because of possible ties to American-bo suicide bomber Monar abu Salha, who blew himself up in Syria in 2014 on behalf of Al-Nusra Front. Salha and Mateen attended the same Fort Pierce mosque. However, FBI agents believed their contact was “minimal” and, again, the investigation was closed.

Aside from the terror claims reported by co-workers, some who worked with Mateen were also disturbed by his language when talking about minorities, other religions and gay people.

“He talked about killing people all the time,” Daniel Gilroy told The New York Times.

Mateen was even less stable at home.

His first wife, who was bo in Uzbekistan and met Mateen on the Inteet, told The Washington Post that he frequently beat her after their 2009 marriage. They reportedly divorced in 2011.

“He would just come home and start beating me up because the laundry wasn’t finished or something like that,” Sitora Yusifiy said.

Mateen was remarried at least once, to Noor Zahi Salman, after his divorce from Yusifiy and had a 3-year-old son.

Salman told authorities the couple had recently been to Downtown Disney as well as Pulse, a federal law enforcement source told People. The trip to Downtown Disney came in April, the source said.

His father, Saddique Mateen, recalled a recent episode in which Omar Mateen became upset when he saw two men kissing in public while he was with his young child. But Saddique may have also contributed to Omar’s worldview. Bo in Afghanistan, Saddique is an eccentric pro-Taliban activist who produced an online video critical of homosexuality just hours after Mateen’s attack.

“It is likely, much like the San Beardino event, that Mateen became radicalized over a period of time as he dove further into the world of ISIS social media and preaching,” former CIA agent Mike Baker said. “It's very likely his Afghan family saw signs of increasing radicalism, but, as is typical, family rarely approaches law enforcement with these waings.”

FoxNews.com’s Diana Falzone and Fox News’ Lucas Tomlinson contributed to this report.