SANTA CLARA -- The 25-year police veteran approached the front door, knowing the woman on the other side had warned 911 dispatchers she would goad officers into killing her.

He was trained for this. Not just the danger, but also for mental health crises experts say account for a growing number of police calls.

Sgt. Alan Wolf never got a chance to use his mental health training, Santa Clara police said. When the door swung open, the woman flashed an aluminum baseball bat. Wolf and Officer Andrew McGuire opened fire.

The department absorbed a torrent of criticism in the wake of the April 13 fatal shooting, with residents incensed by the deadly force used on a woman standing 5-foot-5 and facing three armed officers. Police say it shows that sometimes it is not possible to defuse a dangerous situation, especially one involving the mentally ill.

"At the end of the day, we have to use good judgment and our training accordingly," Santa Clara police Lt. Kurt Clarke said. "These situations are ever so dynamic."

Nearly three weeks later, little is known about the 53-year-old woman who died that afternoon. The Santa Clara County Medical Examiner-Coroner's Office is still trying to find her next of kin. It appears she lived by herself.

Yet she was far from alone. Of all calls made to police across California, 15 percent involve someone with a diagnosed or suspected mental health issue, according to the state commission that oversees police training. In Santa Clara County, the Bay Area county that tracks the numbers most closely, the total is 4,000 a year.

And according to one estimate, in about 40 percent of officer-involved shootings in the state, the victim showed signs of mental illness.

"The police issue of interacting with the mentally ill in crisis deserves more attention than it has now," said Pat Dwyer, a retired Palo Alto police chief and longtime San Jose police captain who coordinates Crisis Intervention Team training for Santa Clara County law enforcement.

From 2005 to 2010 in Santa Clara County, 10 out of 22 officer-involved shootings in the county involved a mental health episode. And in the past five years in San Mateo County, that figure was three in five.

The Santa Clara woman's death shook Bob Cicisly, an experienced suicide and crisis hotline volunteer, who said such incidents make him wonder if notifying police is always the right move.

"This makes me cautious and it makes me scared," Cicisly said. "You're not supposed to be scared to call a cop."

Police in the state get six hours of basic academy training to deal with mental health issues -- far too little, said Dwyer.

But many U.S. police departments -- 2,700 and counting -- have been ramping up efforts to increase the number of police who receive CIT training, a 40-hour state-certified curriculum focusing on mental illnesses, psychiatric drugs, suicidal behavior and a host of other issues. That's the sort of training Wolf had.

Police learn to defuse situations with approaches tailored to such afflictions as schizophrenia and paranoia, and such tactics as turning off lights and sirens and trying to keep the number of officers interacting with the individual to a minimum.

"The most important part of CIT training is learning to de-escalate," said Dr. Scott Zeller, chief of psychiatry for John George Psychiatric Hospital, a member of the Alameda Health System. "There's an understanding, compassionate and collaborative way to help people regain control when they're angry or combative."

He added, "But when officers go to a patient's home, it's right in the heat of the moment. I'm in a hospital where people get searched before I see them, so they're not going to have weapons. I'd have no idea how an officer would feel."

The availability of CIT-trained officers varies widely by agency. In Santa Clara, 34 of 142 officers, or 24 percent, are certified. In San Jose, 37 percent of 1,019 officers are CIT trained. In Oakland and San Francisco, those figures are 12 percent and 15 percent, respectively. Some agencies do provide some form of ongoing crisis training, even if it isn't specifically CIT-based.

A study released in April by the American Psychiatric Association found that CIT-trained officers "had sizable and persisting improvements in knowledge, diverse attitudes about mental illnesses and their treatments, self-efficacy for interacting with someone with psychosis or suicidality, social distance stigma, de-escalation skills and referral decisions."

"We owe it to everyone to get our officers CIT trained," said Zeller, who acknowledged the significant amount of time and money it would take to carry out the task. "The results really justify it. We're going to have far fewer people getting hurt and going to jail instead of getting the help they need."

Still, the training doesn't always prevent disaster. Four officers who had been through CIT responded to a 911 call from the Pacifica home of Errol Chang, who was bipolar and schizophrenic, but Chang ended up dead.

Errol's father, Thomas Chang, said his son threatened his family's safety at least 10 times before they finally called 911 on March 18. Thomas Chang feared police would exacerbate the situation but said the family was "getting desperate."

Errol Chang refused to give up a hatchet he had in his pocket and reportedly stabbed a SWAT officer before police shot him.

Did it have to end that way? Russell Robinson, the Chang family's attorney, said police missed a "golden opportunity" to de-escalate when they subdued Errol Chang with a Taser but let him get up and run into the house. And photos taken by witnesses during the standoff show Chang extending his arms and leg out an open window in what some saw as a signal of surrender. The incident remains under investigation.

Other local police shootings involving subjects in mental crisis have raised the profile of the issue, like the May 2009 killing of 27-year-old Daniel Pham. No CIT-trained officers responded to that call, and it renewed debate over whether San Jose police should automatically send them in cases of suspected mental illness. The department relies on dispatchers and first-responding officers to assess the need for CIT help.

Overshadowed by these headline-grabbing shootings are the "dozens and hundreds of situations that get resolved every day without physical harm," said Chief Kelly McMillin of the Salinas Police Department, a former CIT instructor specializing in "suicide by cop" scenarios.

He said even when a suicidal person voices intentions to confront police, officers can't assume anything until they're on scene.

"The information is sometimes close, and sometimes it's utterly wrong from what they're actually confronted with," McMillin said. "And sometimes, there are no clear answers."

Contact Robert Salonga at rsalonga@mercurynews.com. Contact Erin Ivie at eivie@bayareanewsgroup.com.

POLICE SHOOTINGS AND MENTAL ILLNESS
15: Estimated percentage of police calls in California involving a person experiencing a mental health crisis or who has a history of mental illness
40: Estimated percentage of officer-involved shootings in California that involve a mental health issue
4,000: Estimated number of police calls in Santa Clara County each year involving a mental health issue
22: Number of officer-involved shootings in Santa Clara County from 2005-2010
10: Number of those shootings that involved a mental health issue
5: Number of officer-involved shootings in San Mateo County in the past five years
3: Number of those shootings that involved a mental health issue
Sources: Santa Clara County, San Mateo County, California Peace Officer Standards and Training