Sometimes you just have to leave the dead bodies behind and move on.

That’s the logical thing to do. The smart thing to do. So we’re in another city. San Antonio. There is always a need for math professors at universities. For some reason. Probably the pay. And it isn’t a glamorous profession. The rules of math are nice, though. You get a sense that something is dependable in math. Solid. The rules of how numbers work won’t leave you. People leave. People you love.

**************

Dr. Phillip Morgan looked around the modest apartment and sighed wearily. Boxes still filled the hallways and the living area. Some were open, but a depressingly large number of them were still taped shut. They seemed to glare at him.

“Dad,” a voice yelled from one of the bedrooms.

Phillip surveyed the walls and the floors. Clean. The eggshell-white walls gave the illusion of more space than there actually was, as did the wood flooring. The large windows opened up to an unobstructed view of a park across the street. He could hear kids there, yelling and screaming and having a better time than he was.

“Dad!”

Phillip broke out of his reverie and hurried down the hall. A girl was standing in one of the bedrooms, hands on hips, peering into a box.

“Cassidy. Don’t yell. It’s unbecoming in a young lady,” Phillip entered the room, pushed his glasses up on his nose, and peered at his daughter.

“Sorry, dad, but you weren’t answering. Anyway…I can’t find my table lamp. I know I put it in this box.”

“I tossed it,” Phillip said.

Cassidy looked up, frowning at her dad.

“It was old,” he explained.

“And it was mom’s” Cassidy said, steel in her voice.

“Nevertheless…”

“Dammit, dad! I needed that lamp,” Cassidy glared at her dad, but unlike the boxes, she didn’t do it in silence.

“Language!”

“English. Expletive.”

“Don’t be disrespectful, Cassidy. It isn’t…”

“Yeah. I know. Ladylike. Mom was ladylike and look where that got us?”

Phillip had to agree with his daughter, though he didn’t like it when she argued a point better than him. No eleven-year-old girl should be able to do that to her father. Cassidy had been doing that since the divorce. Since the problems with the police.

“I already got you a new one. It’s in one of the boxes in the living area.”

“Which one?” Cassidy looked at him evenly. It was difficult to tell what she was thinking. Phillip had little experience with girls Cassidy’s age; he dealt with those struggling through linear algebra and complex analysis. They were serious girls, women really, and they never talked back to him.

Phillip held out his arms and shrugged. The boxes were defeating him.

“I’ll order pizza and you can look for your lamp,” Phillip said.

Cassidy looked at her dad, feeling a twinge of guilt. He had been questioned closely by the police about a series of three murders. The victims, if you could call them that, were all known sex offenders and child predators. The experience had made him smaller, somehow. And he always looked tired.

“I’ll order it, dad. Go sit down. I’ll get you a beer,” Cassidy strode to the refrigerator and expertly popped the top of the beer, handing it to her dad. She stroked his thinning hair and kissed his cheek before ordering pizza.

**************

“It’s addition by subtraction, dad,” Cassidy said. The meal was eaten in silence, and it was a silence that weighed on Phillip. What had he done? Now he and his daughter were in Texas, starting over.

“Wha...huh?” Phillip had been lost in a dark study of his life.

“When you subtract a negative value from a quantity, you are actually adding a positive value. Maybe it’s a math property you aren’t aware of, Dr. Morgan,” Cassidy said, laughing.

Phillip smiled. It was a rare occurrence, but Cassidy seemed to have that ability to make him feel better than he should.

“I’m vaguely aware of it. But I don’t see…”

“When mom left, it was like subtracting a negative from your life. Your life will be better without her.”

Phillip looked at his daughter mournfully.

“And what about you?”

Cassidy laid down her slice of pizza and took three large gulps of soda. Phillip winced. He would have heartburn for a week if he did that.

“The additive identity property, dad. Mom made herself nothing in my life when she left us, so it’s like adding zero. Nothing changes.”

Phillip looked at his daughter with grim lips and a sad countenance. What had he done to his sweet, beautiful, slightly rebellious daughter? Here she was, equating her mother with a value of zero. It shouldn’t be that way, despite the abandonment and the divorce. No girl should be without their mother, but it wasn’t Cassidy’s choice.

The father and daughter continued to unpack boxes and set up their new home. Cassidy turned on some music. Mozart. Phillip liked Mozart, though Cassidy called his music ‘stuffy old music from a stuffy old man.’

It was almost midnight when they decided to stop. Rather, Phillip decided to stop and Cassidy went along with it. Phillip felt like Cassidy was catering to him when it should be the other way around. She played Mozart for him. She stopped when he stopped. This didn’t make him feel any better about his worth as a father.

“Cass? I never asked you before, but…well…”

Phillip stopped. He just didn’t want to know the answer. It was bad enough being a suspect in three murders, but it would be infinitely worse if his daughter thought that he had anything to do with them.

“I know you didn’t do what the police suspected, dad. No worries,” Cassidy chugged a bottle of Dr. Pepper and munched on a bag of Cheetos. Phillip thought two things at this instant: his daughter’s choice of sustenance was atrocious, and her demeanor matched her words. She really didn’t think he was the monster that the law enforcement authorities thought he was.

“I was the prime suspect, Cass. No getting around that,” Phillip said. He bowed his head at the reminiscence of the same questions being asked by the cops, over and over. He gave the same answers, over and over. The experience left him questioning the shit that life can throw at a man just trying to live a good life.

“Prime. Yes. Prime numbers have only two factors, both unique. One and itself.”

Phillip looked up at his daughter. She had finished her soda and chips and was currently in search of something else to eat. It would be equally unsuitable for human consumption, Phillip suspected.

“Yes, Cassidy. Wonderful definition. I don’t see…”

“Two factors, dad. You were one. The other one is still out there. The real culprit.”

Phillip sipped his coffee and looked at his daughter fondly. She was mature for her age, mentally as well as physically. The last part caused him some consternation. She had started wearing a bra just this year, and she had her first menstrual cycle three months ago, when all of the trouble started. He didn’t know how he was going to deal with all of this; he felt ill-equipped to talk to his daughter about feminine undergarments and…the other stuff. This thought brought on a rare episode of anger towards his ex-wife. She should be here, helping her daughter become a woman and instructing her about these things.

“You look at math differently than I do, Cassidy.”

Cassidy smiled at her dad. She had found a jar of salted peanuts and was currently engaged in the task of lightening the jar by several ounces. Another Dr. Pepper found its way down her throat. Phillip envied his daughter her body’s acceptance of such vile food and drink. He used to be like that, so many years ago. Things change, however, and not all of those changes are physical. He had lost his faith in the essential goodness of man, the sanctity of marriage, and the belief that good will always prevail.

“Off to bed, old man. I need my beauty sleep, you know. Can’t start a new school looking like a hag,” Cassidy said. She kissed her dad on the cheek and sauntered off to bed, but not before grabbing a Three Musketeers bar to take with her.

Phillip took this opportunity to drink another beer and feel guilty for something he didn’t want to do. It was becoming a ritual that would not soon die out.

**************

It’s so easy to kill these monsters. I stole a Taser from the university one day. The campus police are sloppy about leaving them laying on their desks, and they never lock their doors. And I was never suspected when one turned up missing. Why would I be? A person in my position is not seen as a thief of such items.

The method. Simplicity itself, like most elegant things. Hit the guy with the Taser. Wrap him up in duct tape. Put a bag over his face and suffocate him. Done and done. They will not be preying on someone’s daughter again. As someone I am very fond of once said, addition by subtraction.

**************

The officers found the dead man in his van on San Antonio’s northwest side. He had been bound by duct tape and suffocated with a heavy plastic bag. Records showed the victim to be a registered sex offender who had been in prison for fifteen years for raping his niece. He had also been suspected in several other crimes of a similar nature, but not enough evidence had been found to convict him again.

“Can’t say I’m sorry to see this one go,” Officer Denham said to his younger partner, Officer Sweet. He chewed on his toothpick and looked at the swollen face without emotion.

Sweet didn’t say anything. It was his first dead body, and it didn’t sit well with the hamburger he just ate.

They canvassed the neighborhood and asked questions. No one saw anything except one old lady.

“Saw a kid git in the van with ‘im. Figgered it was her dad. Or his. Couldn’t tell.” The old lady sat on her couch, smoking and drinking beer. She seemed a little put out that the cops were interrupting her afternoon ritual.

“Can you describe the child, ma’am?” Sweet asked this, opening his notebook.

“Yeah. A kid.”

The two police officers looked at each other. The older one smiled faintly.

“Anything else you could tell us about her? Approximate age? What he or she was wearing? Color of hair? Did he or she have a backpack?” Sweet did as he had been taught at the police academy: ask specific questions.

“Sure. A young kid with hair and clothes and a backpack.” The old woman snapped at the officers. Denham stood up, preparing to leave.

“Thank you, ma’am. I don’t think we’ll need any more from you. Appreciate your time,” he said.

The old woman saw them to the door, slamming it behind them and throwing the two locks. The message was clear: you won’t get anything out of me. This told Denham a few things. The old woman saw the killer. The old woman won’t give the killer up. And, perhaps most importantly, the victim was known to the residents of the neighborhood, and they were glad to see him dead. No one was going to tell them anything. No one did. They were lucky to get a civil response from any of the neighbors.

“What the hell, Denham?” Sweet asked the question, irritation in his voice. Sweet wanted to question the old woman more closely, dig the truth out of her.

“She won’t say anything else, Sweet. Nobody here will. Let it go. A very bad person is dead, which is our good luck. Now we won’t have to find some little girl dead in the greenbelts around here. I figure it’s a nice deal for us.”

“So that’s that?”

Denham gave his partner a look that wasn’t seen very often. It was a shut-the-hell-up-and-listen-to-your-partner look.

“Yeah. Fine,” Sweet huffed. But he went along with it. Blue is thicker than blood is thicker than water.

Over the course of the year, three more deaths of this nature occurred. Known child predators were found suffocated after being Tased. The public suspected that a rogue policeperson did this. The police denied it. Dr. Morgan was eventually questioned by Denham and Sweet after they discovered that he had been a suspect in similar deaths in eastern Washington.

The interview was surprisingly short and desultory, with Denham doing all of the talking. Had he seen anything unusual? Noticed anyone suspicious? OK, sir, thanks for your time.

“He done it, Denham. You know he done it,” Denham said, fuming at Denham’s lack of concern.

“I don’t give a damn if he did it or not. Them ones in Washington, either. Far as I’m concerned, he’s done us a service and I’d give the man a damn medal if I could.”

“Besides, I don’t think he done it,” Denham continued. “He ain’t the type. Good man, but not one that takes action of this sort. Hell, he’s a fat math professor with skinny arms. Ain’t no way he could subdue these assholes.”

“He could hit ‘em with a Taser first,” Sweet said. Denham nodded in agreement.

“Sure. But then what? He gonna watch a man die when he puts that clear bag over their head? The man don’t have the stomach for that, trust me. Whoever’s doin’ this wants to watch ‘em die.”

“We’re cops, Denham. This ain’t right,” Sweet argued.

Denham stopped and turned to his partner, lips thin and tight, blue eyes as icy as a witch’s kiss.

“It’s justice. Bad men are dead. San Antonio is a better place because of it.”

Sweet unwillingly agreed. It still didn’t feel right, but it would in a few years, after he had seen more of the horrors that man visited upon man.

The cases of the murdered child predators were never solved, but they did continue to accumulate over the years. No one seemed to mind.

**************

Phillip and his daughter stood in another room filled with boxes, although the number and sizes of the boxes were considerably fewer and smaller than the last time this happened. Phillip didn’t unpack anything, appropriately leaving the task to Cassidy.

“I think it’s a waste, Cassidy. An English degree at Rice University. You could have gone to Stanford. Or Berkley. Or…”

“I wanted to stay close to home, dad.”

Phillip nodded, trying not to let the tears in his eyes become more numerous. His daughter did indeed love him, and this was the only consolation he had in an otherwise unremarkable life.

“You should get another backpack, Cass. This one is more thread than fabric,” Phillip said. He held it up, surprised at the weight.

Cassidy quickly took it from him and laid it in a corner far from her dad.

“You bought this for me, remember? Sixth grade. I love this old thing,” Cassidy said. She smiled at her dad before continuing her task of unpacking in the athletic dorm.

“It’s falling apart,” Phillip said.

“It’s strong, dad. I sew the rips and I duct tape the inside. Practically indestructible.”

It finally came time to leave his daughter, though he was loath to do so. He would be alone now, and he didn’t know how he would face life without the sparkle and light that Cassidy brought to his life.

Phillip drove away, wiping tears from his eyes and being irritated by his runny nose. The three-hour trip back to San Antonio would be bleak and it would feel like an eternity. Remembrances of things past flashed through his consciousness, all involving Cassidy. Time, remembered and lost, sent a dull pain through his head.

Cassidy unpacked quickly and efficiently, munching on Cheetos and inhaling Dr. Peppers. Her backpack reposed innocently in the corner where she had thrown it. After a few minutes of rest and reflection, she opened it to make sure she had what she needed on a daily basis. It was all there.

The duct tape, the Taser, and the heavy plastic bags were neatly tucked away. She would slightly depopulate Houston just as she did San Antonio and eastern Washington. The thought made her smile. Addition by subtraction.

Her dad would be proud of her arithmetic skills.