Recent discovery of terrorist ISIS fighter Douglas McAuthur McCain’s body in Syria has spurred investigation into the radicalization of Muslims within the United States. 

San Diego is fourth on a list of five cities with the most “known or suspected terrorists,” according to recently leaked classified government documents. Following the 9/11 attacks, investigations in San Diego uncovered terrorists and their links to terrorist organizations al Qaeda, al-Shabaab, and ISIS, among others.

Classified government documents obtained by The Intercept include statistics on watch-listed individuals in the U.S. The 2013 document, prepared by the National Counterterrorism Center (NCTC), lists the top five cities with the highest number of known or suspected terrorists (KST) in the U.S. (in order): New York, New York; Dearborn, Michigan; Houston, Texas; San Diego, California, and Chicago, Illinois.

NCTC reports have noted the high level of terrorist activity in Somalia, as terrorist group al-Shabaab has intermittently controlled various key regions of Somalia. A Center for Disease Control and Prevention document cites Office of Refugee Resettlement statistics that list Minnesota, California, Georgia, and Washington, D.C. as locations where the majority of Somalis have settled in the U.S. Thousands have come to the U.S. as refugees under the banner of fleeing war and persecution in their home country. Current population estimates of Somali-born individuals living in the U.S. range from 35,760 to 150,000.

In fiscal year 2014 so far, October 1-July 20, 290 Somalis either turned themselves in or were caught trying to sneak into the U.S. undetected through official ports of entry, according to a leaked U.S. Customs and Border Protection report obtained by Breitbart Texas. In 2010, KPBS reported on circuitous routes taken by Somalis looking to cross into the U.S. over the southwest border. Those routes would take Somalis through locations including Cuba and Tijuana, Mexico before crossing into the U.S.

In November, 2013, three Somali men in San Diego, cabdriver Basaaly Saeed Moalin, local mosque imam Mohamed Mohamed Mohamud, and money transmitter Issa Doreh were sentenced for crimes involving conspiring to or providing material support to the Islamic Somali terrorist group al-Shabaab. An FBI press release described jihadi group al-Shabaab as “a violent and brutal militia group that engages in suicide bombings, targets civilians for assassination, and uses improvised explosive devices.”

Somalia has been marked “a desirable haven for transnational terrorists, something al-Qaeda has tried to capitalize on before, and is trying again now,” according to a Council on Foreign relations analysis.

U.S. Attorney Laura Duffy said of the three men sentenced, “Months of intercepted phone conversations included discussion of suicide bombing, assassinations, and jihad,” according to the release. Evidence at trial showed that the defendants “conspired to transfer the funds from San Diego to Somalia through the Shidall Express.”

Federal Bureau of Investigation’s (FBI) Joint Terrorism Task Force (JTTF) and the U.S. Attorney’s office were commended by multiple people involved in the 2013 case for their tireless and effective efforts to dismantle the effort to provide support for terrorists.

A fourth man, San Diego cabdriver Ahmed Nasiri Taalil Mohamud, was also convicted for charges of conspiracy. “Moalin, a taxi driver, reportedly taught weekend classes at the local Somali mosque. Mohamud, an imam, has led prayer services at Masjid Al-Ansar for the past 10 years,” according to a 2010 post on the Anti-Defamation League website. Masjid Al-Ansar is located just over a block from Masjid Nur.

Breitbart recently reported that Masjid Nur is the mosque associated with Douglas McAuthur McCain, an American recently killed fighting for ISIS in Syria. McCain was from Minnesota, but worked and went to college in San Diego.

August 29, Breitbart Texas released a newly leaked document from the Texas Department of Public Safety, warning federal agents of ISIS’s active efforts to exploit weaknesses in the U.S. southwest border. The warning referred to “Outright calls for ISIS to infiltrate the southwestern border through Mexico to stage terrorist attacks.” Though the report focused on Texas, Breitbart Texas confirmed agents received the ISIS terror warning across the entire U.S.-Mexico border.

In December, 2012, San Diego woman Nima Yusuf was sentenced after admitting to conspiring with multiple Minnesota al-Shabaab recruiters to provide money and personnel to fight under al-Shabaab. According to an FBI report, Yusuf tried to recruit a local San Diego man to fight for al-Shabaab. In a 2010 phone conversation, Yusuf “suggested that America was responsible for the 9/11 attacks and expressed hope for an even greater catastrophe in the future: “Oh. It will be happening again. Trust me, more this time it will be double…triple their deaths. [Laughter.]”

Infamous 9/11-associated terrorist Anwar Al-Awlaki, born in America, moved to San Diego in 1996, where he attended graduate school and served as imam at the Rabat mosque, ABC News reported. While in San Diego, Al-Awlaki met with an associate of “Blind Sheik” Omar Abdel Rahman, a terrorist “convicted in connection with the 1993 terrorist attack on the World Trade Center.”

Al-Awlaki also met with the first two of the 9/11 hijackers who entered the United States during his time in San Diego. Khalid al-Midhdar and Nawaf al-Hazmi reportedly rented apartments in Clairemont, took flight lessons at Montgomery Field, attended Al-Awlaki’s mosque, and had private meetings with him to discuss attacks on the USS Cole and 9/11. Officials, according to 10 News, say Al-Awlaki advised the “underwear bomber” and attempted Times Square bomber Faisal Shahzad.

Al-Awlaki once was considered a moderate Muslim before leaving the states and was recorded as saying, “Islam is a religion of peace” in a 2001 Washington Post video. In 2002, living at his family’s home in Yemen, Al-Awlaki created online videos “preaching jihad against the United States,” according to ABC.

Another 9/11 hijacker, Hani Hanjour, was identified as having San Diego connections. After the attacks, four more San Diegans were arrested as material witnesses, and three were charged, ABC reported.

Law enforcement and intelligence efforts in San Diego are hailed as part of the reason that San Diego has not seen a greater level of terrorist activity. Unique qualities make San Diego a draw for many around the country, including terrorists. Programs operated by the FBI and the JTTF, the San Diego Sheriff’s department and Police department, as well as information provided through the county website have reportedly aided in suppressing activities of terrorists present in the region.

Exponentially increased traffic at the southwest border in recent years provides yet another opportunity for enemies of the U.S. to obtain access to the country. It is the men and women of U.S. Customs and Border Protection that provide the country with a first line of defense to prevent more terrorists from entering the country.

Follow Michelle Moons on Twitter @Michelle Diana