Hardening physical barriers represents one way to improve security. Hawaii State Hospital has begun that task, to prevent a recurrence of last fall’s incomprehensible escape by a patient hospitalized rather than imprisoned after killing a woman in 1979.

But more than new fencing, keeping the public safe means ensuring that staffers who oversee the patients and hospital grounds have the full vetting, supervision and training required for the job.

Oahu residents, particularly those who live within easy reach of the Kaneohe facility, are understandably frustrated. The escape of patient Randall Saito — who got to California before his absence was discovered and reported — remains a mystery months after the Nov. 12 incident.

Saito pleaded not guilty Tuesday to the charge of felony escape, following his extradition back to Oahu, and he remains in custody in lieu of $500,000 bail. He was captured Nov. 15 in Stockton, Calif., three days after he walked off the hospital campus. The case put the state institution in an intensely embarrassing light.

Saito apparently had help with his escape — evidenced by the cash and cellphones he had without authorization and the fake IDs that enabled it. Although it’s not established that any of the help came from within the hospital staff, it’s plain that some protocols need to be changed.

And although the criminal and administrative investigations are still ongoing, surely those supervising him let their guard down, at a minimum.

For example, Administrator William May acknowledged that they are reviewing the institution’s policy about disseminating personal mail, a route through which a patient could receive contraband items. Currently, he said, mail is not opened by staff unless “we have a reason to suspect something may not be appropriate.”

A scan of online documents of various state and local forensic psychiatric centers shows that many do open mail in the presence of a staffer as the rule, rather than the exception. Handing over postal packages is seen as especially risky.

It is good that the state hospital is seeking a better balance between patient’s rights and general security.

An informational briefing last week brought hospital officials before the Senate Committee on Commerce, Consumer Protection and Health and the House Committee on Health and Human Services to explain the escape and security measures planned and underway.

An interior fence 12 feet high is being built, with plans for another fence outside, enclosing the grounds. That’s fine, but what lawmakers and the public really want to hear is more about the actions, and inactions, of the people within.

The seven people placed on 30 days of unpaid leave immediately included six employees and one contract worker, officials said. The contract worker has not returned; the six staffers are now on paid leave, under a union agreement, and one more staffer went on unpaid leave last week, according to officials.

Appalling details from new court documents revealed what surveillance video captured of the escape. Saito was able to tape door locks in one of the buildings, retrieve a garbage bag filled with clothes from a combination-locked cabinet and walk off the grounds through a combination-locked gate.

The questions this raises are obvious: How did he get the combinations? Why wasn’t the taping discovered in a routine inspection? How did he have more than $6,000 in cash, two fake ID cards and two cellphones?

The breach in security here involved people, and that’s not an ailment cured by higher fencing.

When the criminal investigation is done in the next several weeks, the Office of the Attorney General owes the public a fuller explanation of how the failure happened. And the hospital is obligated to prove it has corrected its lapses in personnel management.