Five terrifying facts we've learned about the San Bernardino terrorists

How many more are out there like them?

As officials investigate the couple responsible for the San Bernardino terror attacks, they are learning some chilling facts. Here are five things about Sayeed Farook and Tashfeen Malik that has authorities worried.

LOS ANGELES, CA (California Network) - There are three details about the San Bernardino terrorists that have authorities worried. Normally, terrorists are young, Middle Eastern males, often unmarried and with few social connections. They're radical and religious and often spend considerable time with known radical clerics. They come from poor background and tend to be disaffected. But in the case of Sayeed Farook, 28 and Tashfeen Malik, 27, the circumstances are scarily different.

1.    Sayeed Farook was a U.S. citizen who didn't appear threatening. Farook was born in Chicago, the son of Pakistani immigrants. He attended public school, earned a degree, enjoyed working on cars, and didn't really talk about his religion at all. He visited dating websites in his quest to find a wife. He worked for the Department of Public Health and enjoyed a $70,000 annual salary. By all observations, he was a normal American citizen with a good job, a wife and a home. He was living the American dream. Friends described him as "quiet" and "soft."

2.    There was an exception to Farook's quiet demeanor. Coworkers have revealed that two weeks before his bloody rampage Farook got into a debate with his coworker Nicholas Thalasinos, 52, who was a Messianic Jew. The debate was whether or not Islam was a peaceful religion. Thalasinos was one of the victims killed in the terror attack. He told his wife he did not think Farook would do anything dangerous.

3.    Tashfeen Malik underwent a full FBI background check, and passed. Malik's family originally came from Pakistan.  She met Farook online, and the couple was married in Mecca in 2014. There were no indications that she had radical inclinations.

4.    Malik was the mother of a newborn baby. Farook and Malik left their six-month-old baby with his parents in Redlands. When Malik left the baby, there was no indication that anything was wrong or out of sort, according to Farook's mother. There was no sign of distress and the goodbye wasn't unusual. Malik hid her intentions so well that when news of the attack broke, she feared her son might be among the victims.

5.    Despite all appearances, the Farook and Malik were supporters of ISIS and Malik pledged allegiance to Abu al Baghdadi, the leader of the Islamic State. Is it possible that she was the leader of this husband and wife terror cell and that she led the attack against her husband's coworkers?

It's chilling to consider that until the moment of the attack, there was nothing to set Farook and Malik apart from any other Muslim couple. Farook was a citizen, with an education and a good job. His brother was a decorated Navy veteran. Malik passed an FBI background check and had a baby. Farook's mother, their landlord, friends and neighbors, noticed nothing exceptional.

There was no warning. How many more are walking among us, waiting?