Scott Davis, who runs the mental health crisis intervention team training for first responders in Rockville, presides over a simulation during his class. (Bill O'Leary/WASHINGTON POST)

When James Lee showed up in Silver Spring in February 2008 and delighted a crowd by scattering fistfuls of cash in a bizarre anti-Discovery Channel protest, police arrested him for disorderly conduct — and littering.

Two-and-a-half years later, Lee walked into the Discovery building with a bomb on his back and took three hostages, sending workers and about 100 children — who he referred to as “catastrophic pollution” — scurrying. He was killed by police before he could detonate the device.

It wasn’t hard, last week, for the local law enforcement officials who make thousands of mental health calls a year to imagine a worst-case scenario that ended with the slaughter of children, as the nation witnessed at the Sandy Hook Elementary School in Newtown, Conn.

As police officers in Montgomery County have added mental-health triage into their daily duties, a common question hovers over many of the interactions: Is today’s case a health problem, or a violence problem?

The range is daunting. In Montgomery, there is the veteran who has barricaded himself from police multiple times, leaving officers concerned the danger could escalate. There is the man who has spoken at a public meeting about being “a victim of covert harassment” — and could be a threat.

And there are hundreds of sad but benign cases, like the woman who hid out on a police-headquarters fire escape and then kept telling the officers, “Do not inject me!” Or the person known to officers as “Karate Man,” who they have repeatedly taken in for psychiatric evaluation.

And there are countless others whose condition or history police know little or nothing about.

Officer Scott Davis has helped hundreds of Montgomery officers navigate the blurry areas between sickness and public safety. He’s heard the assumptions, and once held them himself: “There are places for those people,” the ones paralyzed by voices, or suffering after psychotic breakdowns — or who don’t even know they’re sick.

He now understands that the mentally ill in need of professional care are everywhere, beginning with “the streets.”

And parents’ houses, and sketchy apartments, and upscale neighborhoods.

Davis races around Montgomery acting as a fast-talking bridge between law enforcement and the people who treat, and those who need treatment for, mental illness. He joins routine calls and SWAT take-downs. And as coordinator of the county’s crisis intervention team for mental health cases, he helps organize quarterly sessions that have trained more than 1,200 officers from Montgomery and elsewhere by putting them together with therapists, more experienced officers, and other specialists.

Part enforcer, part advocate, Davis slides easily between the lingo of street cops, social workers, and doctors.

“I don’t think people take mental health emergencies as seriously as they do somatic emergencies, like heart attacks, cancer, strokes and things like that,” Davis said. That’s true for the patients as well. “It all comes down to lack of insight. These guys don’t know they’re sick. They think everything’s cool.”

Crisis intervention teams like Montgomery’s have spread across the country following the nation’s move toward treating serious cases of mental illness in community settings rather than in large state-run or other institutions. Mental health providers say that the so-called deinstitutionalization effort failed to come with the funds needed to cover local care for those who need it.

Michael T. Compton, a professor in the psychiatry department at George Washington University’s medical school who has studied such teams across the country and worked with them in Georgia, cites estimates that 10 percent of all police encounters involve people with serious mental illness.

“The vast majority of those interactions don’t involve a high-risk threat to public safety. It’s the guy standing on the corner who’s panhandling,” Compton said. “We’re trying to dispel this myth that mental illness equals violence or dangerousness, because in the very vast majority of cases it doesn’t.”

Still, police often see the mentally ill at their worst, and they are saddled with the treacherous task of figuring out who might cause harm.

In Montgomery, Davis helps arm officers with lessons on the contours of bipolar disorder, cheat sheets of psychotropic drugs, and ways to de-escalate confrontations and spot suicide danger signs. And he points officers toward county therapists who operate a 24-hour crisis center and head out on calls in the field for insights and future advice.

One of those therapists, Mary Witteried, always tells officers the same thing: “You need to know the law. People are allowed to be crazy.”

She reminds them that being mentally ill doesn’t make them a threat. She also shares stories from more than 35 years dealing with a slice of the mentally ill that tends toward the extreme. The patients who find themselves approached by police or taken to a crisis center, by definition, are generally not the most stable or well-adjusted, she said.

She gives officers tips on crucial interviewing techniques. An important one: When someone is having “command hallucinations” ordering them into action, ask the patient what the voices are telling them to do.

A couple years ago she asked an intoxicated homeless patient that question.

“He told me the voices were telling him to kill me with the knife he had in his pocket,” Witteried said.

She ran out an automatic locking door, and wrote up an emergency evaluation petition, which can be used to temporarily hold a person against their will pending a hearing on whether they remain a threat to themselves or others.

As she handed the police the emergency petition, the man screamed more obscenities and death threats at her. The officers overruled her and jailed him instead.

There’s also the problem of what police call “repeat customers.”

It gets particularly tricky when officers repeatedly come in contact with a person they know has a violent history, but who isn’t clearly a threat at a given moment.

Witteried’s experience is that those who have been dangerous in the past are more likely to be dangerous again, she said.

“You’re really walking that fine line of, ‘You haven’t crossed the line of dangerousness yet, but you’re headed that way. You still have your civil rights. You still have your freedom, even though you’re mentally ill,’ ” she said.

The tension between rights and safety is not just thorny for law enforcement but families as well.

There are cases where family members are worried enough to petition for a loved one to be involuntarily committed for treatment, only to have a judge rule that such longer-term care cannot be foisted upon an unwilling person.

“Once they get stabilized on their medication, the doctor may say, ‘They are no longer a threat, I’m not going to sign commitment papers. I’m going to release them,’ ” said Steve Chaikin, an assistant state’s attorney in Montgomery who has been involved with such cases. Or perhaps the individual is simply very good at pretending. “Who is the real person? . . . It’s a scary area.”

Once they’re out, everyone has to hope the person doesn’t take a terrible turn, he said.

“You just stay in touch with the families, and you just have to have hope the family is going to keep a close eye on the person,” and quickly call police if they become threatening or violent again, Chaikin said.

“It’s a very difficult and gray area, and it’s extremely frustrating for the police, the citizens, the doctors and everybody involved, and most frustrating for a victim” if there was one, he said.

Officers sometimes stop at the homes of certain repeat customers to check in with them or their loved ones, or ask after the homeless mentally ill on the street. But a general lack of follow-up remains a key weakness in the mental health system, Davis said.

He has handled more than 100 people in crisis, and knows that some of them, like the man who had a psychotic break and complained of “covert harassment,” remain potentially dangerous. But there are so many new crises he can’t keep up with all the old ones.

“He’s out there. I have no idea what he’s doing now. He lives with Mom and Dad and hopefully when he starts going off again, they’ll know enough to call the police,” Davis said.

The shootings in Connecticut are a reminder of why he and others do the work they do. But Davis said they are also a reminder of how much remains undone.

“I’m not surprised, and I’m not going to be surprised when one more happens,” Davis said. It may be reality, but it’s not something he can accept. “We’re doing all we can to prevent another shooting like that.”