PITTSBURGH — State regulators said they will rely on a police investigation at a psychiatric clinic where a gunman opened fire, killing one person and wounding several others, and the hospital’s internal probe to assess whether it followed protocols meant to keep patients and employees safe.

The departments of health and public welfare, each of which has a hand in inspecting and regulating Pennsylvania mental institutions, said Friday they have no immediate plans to conduct an on-site probe of Western Psychiatric Institute and Clinic. Police shot and killed the gunman, John Shick, to end the rampage Thursday.

“I think we need to find out from the police their part of the investigation, and we need to wait for Western Psych to do their internal investigation and make a determination at that point,” Health Department spokeswoman Holli Senior said.

“We’ll determine whether the proper protocols were in place and whether the hospital followed those protocols, or if the situation could have been handled in a different manner, and we’ll address those concerns at that time,” she said.

Experts who have studied workplace violence say there’s no foolproof way to protect such clinics.

“It cannot become a fortress,” said Larry Barton, a professor of risk management at The American College in Bryn Mawr, Pa. “The options for an employer are exceedingly limited, especially for a psychiatric institution.”

Barton, who is also an instructor in threat management for the FBI, said he agreed with the clinic’s decision not to arm its security guards, since doing so would just create more risk for patients and staff in an already volatile workplace.

He noted that patients at a psychiatric institution may have excessive anger, excessive depression, be over-medicated or be under-medicated. Yet the institution’s core mission is to accept and treat such people 24 hours a day, every day of the year.

“It’s got a public mission. It’s a public charity,” he said.

“The best it can do is try to be accommodating and smart. With this type of facility it is roulette.”

Barton said it would be highly unusual for Shick’s attack to have been truly random.

He said more than 97 percent of people who commit these types of workplace homicides have some connection to the place of the shooting. However, the tie might be through a friend or relative, he said, or someone who works at the facility.