SAN BERNARDINO, Calif. >> In the offices of the Inland Regional Center, Christmas did not come.

Tinsel still festoons cubicles. A small tree with presents sits undisturbed. A sign-up sheet to bring in food remains empty of names.

The staff was still gearing up for the holidays on Dec. 2, the day 14 people were massacred on the center’s gleaming campus.

Few of its 600 employees have gone to the office since, other than a brief visit to gather personal belongings a week after the terror attack.

On Monday, they return.

While many have continued to work, visiting the homes of autistic children and mentally disabled adults, they haven’t been together in the place where everything froze once law enforcement officers whisked them away.

Amid the investigation and cleanup, the campus has been locked behind a chain link fence wrapped in green mesh. Within that perimeter, in one corner, is a second fence.

It seals the conference center that San Bernardino County’s health department was renting for a holiday luncheon when the two attackers began their assault. A county restaurant inspector targeting his co-workers was joined by his wife in killing 14 and injuring dozens.

The conference building will not reopen Monday, and it’s not clear when it might.

For now, the act of reuniting elsewhere on campus will be a huge step forward for Inland Regional Center staff. They miss the friendly faces, the hallway chit chat. They yearn to renew a sense of stability at an institution unmoored by violence.

“That’s what I’m hearing from them: ‘We want to be together again. We want to be back at work,’” said Lavinia Johnson, the center’s executive director.

Sitting for an interview in a tidy courtyard shaded by two of the center’s large, red stone buildings, Johnson and associate executive director Kevin Urtz reflected on the reopening. Johnson apologized for tree debris that has collected in the absence of caretakers. Several Japanese maples still clung to the last of their red leaves.

The plan for Monday morning is, after a welcome and some food in the lounges, to do what social workers and counselors do best — sit and talk.

“Just be together again,” Johnson said, “share where they’re at.”

After that, it’s back to work. Professional counselors will be available for employees who want them.

“Our goal is to help people help themselves. And that’s pretty much the same strategy that we want to take with our staff,” Urtz said. “You know, help them through this.”

Both have worked more than 25 years at the Inland Regional Center, which with nearly 31,000 disabled clients in the working-class sprawl east of Los Angeles is the largest of 21 in California. It is a vital community resource in a place where about one-third of households live below the poverty line.

Johnson and Urtz expect staff to be resilient, in the spirit of the #SBStrong phrase that has become a community rallying cry. They thanked law enforcement and expressed condolences for the families of the slain.

While people want to move ahead, Urtz doesn’t expect ever to put that day behind fully.

“I don’t think we’re ever going to just, you know,” he said, with his voice trailing off. “No, it’s too big.”

At the same time, with strengthened security, both said they are confident that the site is safe. After all, center employees or clients were not the focus of the attackers, whom the FBI says were motivated by radical Islamist beliefs.

Last week, Johnson was preparing for the reopening when she stopped by her office.

While there, she put away her Christmas decorations. And she thought how, this year, she didn’t get to enjoy them.