It wasn't unusual for a state trooper to meet with a school resource officer, so Petronia walked into the high school in her uniform but unannounced. She approached the front desk and asked for Custer Graham. The lobby was busy with teachers and students getting ready to start their day.

A few minutes later, a tall man approached wearing a navy-blue suit, white shirt with red necktie, and looking squared away. He appeared to be in his late fifties but still physically fit. Although he wasn't in a police uniform and didn't carry a firearm, she recognized him by his demeanor. Detective types never lost their swagger. Even after retirement they carried themselves in a certain way, cocky and confident.

"I'm Trooper Petronia Henning." She extended a hand.

The man had a firm grip, but not crushing. "I'm SRO Graham. What can I do for you?"

Straight to business. Petronia liked that. She hoped she wouldn't receive an urgent call, because she was outside her patrol area. The quicker she could get back the better. "Can we speak someplace private?"

Graham turned and motioned for her to follow. He led her into a conference room off the busy lobby area and closed the door. "Is this about a student? Is one of them in trouble?"

"I'm here to ask about your time with the PSP, specifically about one of your open unsolved cases, the convention center robbery."

Graham's eyes went wide. "I can't discuss that."

"Why not?"

"If you checked into it, then you know why."

She tried appealing to his ego. Men like him didn't like being reminded of their weaknesses. "Exactly who are you afraid of?"

He squinted. "Look, Trooper Henning, I was ordered to stand down and turn over my case files. I wasn't threatened. I have no reason to fear. I only followed orders." He looked at the clock on the wall. "Unless you have something else, we're done here. It's the start of a busy day."

He turned to leave. Petronia knew she had only one more shot. If she couldn't appeal to his ego, she might be more successful appealing to his sense of pride. "I understand you were one of the PSP's finest detectives. The convention center robbery was one of your only unsolveds. That has to bother you."

Graham laid his hand on the door knob but paused.

She kept talking. "I've only been a trooper for four years, but one thing I picked up on is how detectives always carry unsolved cases in the back of their minds. Even after they retire. Always thinking about them. Always puzzling out how there might be one string they could pull to make the case unravel and always looking for that string."

Graham remained silent.

"There's been a break in the case," she said. "Someone has come forward who may have knowledge about the missing money."

He turned to face her and pressed his back against the door. "Who else knows about this?"

"My barracks commander." A lie of omission, Petronia knew. Lieutenant Jardine had given her permission to work a hobby case, but he wasn't aware of the details. Graham didn't have to know that.

"Has the case been reopened?"

She had the urge to lie about that too, but her gut told her to play it straight. "No. If the connection to the missing money pans out we might be able to force the case back into the daylight."

Graham regarded her. "How exactly do you think I can help you?"

"Tell me what you know."

He took a few moments then pointed to the conference room table. "You better have a seat."

After they both sat, Graham spoke. "I don't have much to tell you. After the robbery, I interviewed the personnel at the convention center. All cash from paid parking and gate sales was secured in a high-tech vault on the premises. Their SOP was to leave the cash in the vault overnight and have it picked up by armored car early the next morning."

Petronia interrupted. "Did your case files include details of your interviews?"

Graham looked at her like she was incompetent. "Of course. Interviews, details of the armored car pickup, schedules, procedures, a detailed timeline, everything."

She knew an experienced detective would cover all the bases and felt a bit silly for having asked, but she wanted to verify that the case has been completely investigated. "A detailed timeline? When did the theft occur? When was it first reported?"

"The theft occurred after everyone left for the evening and the center was locked up."

She perked up. "How were you able to determine that?"

"Security camera. The robbery was well-thought out and professional. Alarm systems and central camera system were disabled, but there was one camera in the vault area independent of the main system. That camera time stamped the photos."

She gripped the side of the conference table. "Are you telling me you had photos? Face shots?"

"A little grainy but yes." He sighed. "As soon as the brass became aware of the photos, that's when I got shut down and was asked to turn over everything."

Petronia read something in his expression. "Did you turn over...everything?"

Graham hesitated. "Having to give up that case was the lowest point of my career with the PSP. The impropriety of it all kept me awake at nights until I eventually had to leave. Since I had enough years of service, I retired. Now I work for the municipal police as a SRO." He lowered his voice. "Shutting down that investigation was wrong. I still feel that way."

She pressed him. "You couldn't let go, could you? You still held onto something, maybe thinking one day you'd find that string to pull I mentioned earlier."

"You're treading into a mine field. If you keep pushing, very bad things might happen to you."

"That's my problem. What do you have?"

Graham looked her in the eye. "There were a lot of photos. I didn't think they would miss just one of them."

He had kept a photo of the perpetrator. She easily put it together. "Someone recognized the thief. Someone in power was trying to protect him or her. Who is the perp?"

Graham shrugged. "I honestly don't know. By the way, it's perps not perp. There were two of them."

Two of them? That means Neil Mantener didn't act alone. Have you figured out yet who the second perp might be?