by Austin Bay December 9, 2015

The old proverb speaks to the difficulty of finding the rare and concealed amid the normal and visibly numerous: Within the haystack, the needle hides.

The terrorist couple who murdered 14 people in San Bernardino, California, were radical religious murderers hiding among loyal, law-abiding Americans. Forget the needle. Tashfeen Malik and her husband, Syed Rizwan Farook, were daggers. They didn't cut hay; they assassinated loyal, law-abiding Americans among whom they lived and worked.

According to investigators, Malik had pledged her fealty to the Islamic State group. Her pledge to the group makes her a traitor. The religion she espoused has explicit political objectives, to include the overthrow of the U.S. government and destruction of the U.S. Constitution in favor of a foreign power.

Treason also involves duplicity. Malik entered the U.S. under false pretenses. She abused America's liberal immigration regimen. Farook, born in the U.S., turned on his native country. They abused America's liberal immigration regimen and had a child in an American hospital. They pretended to mix in San Bernardino's melting pot. And yes, America is still a melting pot of humanity -- socially, ethnically, culturally and spiritually. The diverse origins and faiths of the people Malik and Farook murdered confirm it.

In the lingo of security agencies, terrorism is a type of distributed offensive threat. Malik and Farook are a hideous illustrative case. The couple planned to ambush unarmed civilians; they were an offensive threat. "Distributed" is the difficult word. A terrorist can select from a range of targets "distributed" throughout an area. In this case, they chose a regional human services center in San Bernardino. They could have bombed a bus going to Disneyland. The defense cannot protect everything. Police are "distributed" throughout an area. So are surveillance cameras. But terrorists can evade them.

Terrorism's "distributed" threat is one reason the National Security Agency looked for clues in cellphone metadata, but that resource is now heavily restricted. Advocates of concealed handgun carry permits point out that armed citizens are a "distributed defense" to counter crime and terror. This is a very compelling argument but is one zealous gun controllers tune out. They shouldn't.

Six years ago, a retired FBI agent told me that some of the best sources for stopping a domestic terror attack are tips from citizens. American Muslims provide good tips on potential Islamist-inspired terrorists. They know their community. Counterterrorism isn't cops on the beat, but there are similarities.

That made sense to me. In 2003, I had a cup of coffee with an Arab Muslim friend of mine. I asked him for an update on The Quest -- his long pursuit of a permanent resident green card. He sighed and then said, softly, "There are 25,000 Arab Muslim men in my group (green card applicants), (and) 24,991 of them are like me, Austin. We know what it is like -- to live in fear of terrorists, criminals, dictators. We left to come here ... to get away from them. But the other nine? They are very dangerous people." He paused and then added, with unmistakable resignation, "I guess that's just my lot in life."

I heard the resignation and told him I could vouch for him. No need. His attorney told him to continue to work hard and wait.

I asked him where he got the number "nine." I knew he meant potential terrorists and spies. He thought for a moment and then replied: "Well ... it seems about right. There are not many (violent Islamist extremists). ... They're crazy, you know." We explored his gut estimate. If nine out of 25,000 is right, then we've got 90 in 250,000. Ninety heavily armed fanatics can seize a city. Yes, "very dangerous people."

He eventually secured his green card. Then he went to Iraq as a translator. He is very proud of that service. A few weeks ago, he wrote me an email and said he expects to become a citizen at some time next year.

We need to do a better job vetting immigrants. That isn't bigotry; that's sanity. However, loyal, responsible immigrants strengthen America. Americans who happen to be Muslims are -- like my friend -- a key line of defense in stopping Islamic State-influenced terror attacks.