Editor's note: We are pleased to present the concluding episode of a two-part mystery story by Julia Richards, with sketches by Elicia Preston. Use the navigation tool at the top right to catch up with Part 1.

Being a Health & Safety Inspector meant being observant, picking out hazards as you walked through a room. It also meant being knowledgeable, knowing where to look, where the most likely dangers would be.

To Todd, it meant something else as well. He had been doing this job for twenty years, and sometimes he could just walk into a lab and know something was wrong. It was unscientific, but those hunches always proved right.

He lifted the lid of the dry ice chest.

See, it’s just an ordinary cooler, he thought. It was about half full of dry ice with a layer of thick padding covering it to prevent evaporation.

Just some ordinary insulation foam, Todd told himself. Oh, there’s a hole on the corner of the foam. Should I write that up? I guess it’s not technically a hazard. Everything looks good. Just some long blonde hair on the foam. Oh god...

“What’s going on?”

This time Dan had snuck up behind him. “You shouldn’t put your head in there too long, you know. Heh, not that I’m telling you how to do your job.” He went back to playing with his phone.

“Is everything okay?” Rachel asked. “You look a bit unwell.”

“Could we hurry this up?” the professor asked as he joined them. Anna followed silently behind. “I’d like to get on with my writing.”

Todd didn’t answer. He had seen something as he pulled up the corner of the foam, a glimmer of orange. He pulled on one of the thick insulated gloves by the cooler and fished the object out. It was a gummy bear, frozen solid.

“Oh my god, Dan, what did you do?!” Anna screamed as she lunged, her pale fists flying at his face. Professor Denslin grabbed her about the waist and tried to pull her away. Todd felt like he might faint again.

Suddenly, the door slammed. “Okay, everyone,” Rachel said as she walked back from the door with a gun in her hand, “Let’s all calm down.”

“I’m sorry, but Anna has a history of violence. I assure you that I have all the necessary permits to carry a concealed weapon in this state,” Rachel said after they had all sat down. They were staring at the 100-pound girl in total terror. Dan’s mouth had yet to close.

“It was one case of assault against an ex-boyfriend,” Anna said in a hoarse voice. “The charges were dropped.”

“Well, this city has a high violent crime rate,” Rachel said, “and my father wanted me to be prepared. Also, it’s not loaded.”

“Why the hell wasn’t that the first sentence out of your mouth?” Dan said.

“I was really worried Anna might try to hurt you. I just wanted her to stop her. I only load the gun when I’m about to walk home.” Rachel, looking confused, lay the gun on the desk.

“You have a gun, and you were worried about someone hurting someone else?” Dan said with a laugh. “This is nuts! Let me out of here.”

He started to stand, but Anna reached out and grabbed his wrist. “What did you do to Melanie? Why was there a gummy bear in the ice cooler with her?”

“Wait, how did you know Melanie was in the cooler?”

“Melanie was in the cooler?” Rachel said.

“What the hell is going on?” the professor asked.

“Wait a moment!” Todd put on his most authoritative inspector voice. “Dan, what do you know about Melanie’s death? Clearly, you know something.”

“I came back to lab around midnight the night she died,” Dan said nervously, “but I swear I was just adding more dry ice to my overnight reaction. I opened the cooler and there she was! All curled up on the foam padding. I freaked out! I might have had a mouth full of gummy bears at the time. One must have fallen out.”

“That’s disgusting,” Anna said, but she looked like she believed him. Indeed, Todd didn’t think that was the kind of detail a murderer would make up. Also, the bear he had found did seem to be partially chewed.

“And how did you know she was in the cooler when she was found on the desk?” Todd asked Anna.

“I came in around 12:15, and the cooler was open,” Anna said, “so I went to close it. I pulled Melanie out, and I guess I must have laid her on the desk. I was in shock. I know I checked for her pulse though, and it was too late.”

“So two of you found the body of a co-worker and decided to just leave it? Not to call for help?” Todd asked. He did his famous skeptical eyebrow raise. Neither Dan nor Anna answered.

Todd said sharply, “Anna! Why were you in lab at that time of night?” She was still silent.

“Anna, you should just say,” Rachel interrupted in a helpful voice. “She was probably here to meet the professor. They have sex in the lab sometimes.”

“WHAT? ON WHOSE DESK?” Dan yelled. The professor and Anna both looked mortified enough for Todd to believe it was true.

“All right,” Professor Denslin said, “We’re both consenting adults. None of this is related to poor Melanie’s death.”

“Were you in lab that night?” Todd asked. “Waiting for Anna?”

“I came in just before midnight, if you must know," he said. "I found beer bottles on Melanie’s desk.”

“Melanie actually did come here a lot to drink when no one else was around,” Dan said. Todd looked at him in disbelief.

“I guess I should have stopped her before, but she was just letting off steam. Her parents wanted her to be a doctor. They rode her pretty hard,” Dan added sheepishly. Todd sighed and turned to the professor.

“But Melanie wasn’t here when you came in?”

“I looked around but didn’t see anyone. Then I heard some knocking noises. I thought it was coming from the closet, but after a few minutes it stopped. Then I thought about the dry ice chest. It’s the one of the only places big enough to hide in here. I opened it but she was already dead. She must have just climbed in there to hide from me and suffocated in less than a few minutes.”

“Poor Melanie,” Rachel said. “She was terrible at chemistry. She only passed my class because I gave her some extra credit assignments.”

“She must have burned her finger through the hole in the foam,” Todd said. He thought about the girl lying in the cooler, the oxygen in her lungs pushed out by the carbon dioxide.

“But you also just left her body?” Todd asked Professor Denslin.

“I know her parents. That’s why she was working in my lab. I just couldn’t face them. I’ve got a son that age. I cleaned up her desk and ran.” The professor’s voice finished in a ragged sob and he buried his face in his hands.

“And you thought the professor might have killed her,” Todd said to Anna, “so you kept quiet.”

“I know he is not a killer,” Anna said fiercely, “But he didn’t show up or say anything about that night. I didn’t want to get him in trouble.”

“That’s some sound reasoning, Dragon Tattoo,” Dan said.

“What’s your excuse?” she snapped back. “At least I pulled her out of there and tried to help her. I’m not a robot like you all think! I did like Melanie and seeing her like that was horrible!”

“Honestly, I was pretty blitzed myself,” Dan said in a small voice. “I wasn’t thinking straight. And afterwards, I dunno, it seemed like it must have been alcohol. That girl drank like a fish.”

“Poor Melanie,” Rachel said again.

“That’s enough! I’m calling the police, and we’re all going to tell them the truth this time,” Todd said. “Professor, you let Melanie work in your lab unsupervised when she was terrible at chemistry. Dan, you knew she was getting drunk here and just let it go. Anna, you lied to the police to protect someone who might have been a killer! Rachel, you shouldn’t be waving a handgun around, even if it is unloaded. Use some common sense. This is how accidents occur: thoughtlessness on the part of every person who could have stepped in and made a difference.”

He pulled out his phone to call 911. This is why I get out of that cozy bed every day, Todd thought: Health and Safety, making sure people are well and well-protected, not completely surrounded by lunatics.