"Oh, good. You're home."
I hurried across the patio but stopped several yards from the pool. The bag was still in her hands, and I didn't know what she'd put into the water.
"Step away from my pool."
She tilted the bag again, shaking out more of its contents.
Then she laughed harder.
"You think you're going swimming after this?"
I stared at her.
"What did you put in there?"
She stepped toward me and pointed at the water.
"Brain-eating amoebas, sweetheart. Let's see how much you enjoy your precious private pool now."
The words struck me like a physical blow.
For a moment, I couldn't speak.
She had just claimed to introduce something potentially deadly into water that my family used regularly.
My sister's children were supposed to arrive in less than an hour.
The younger one was only seven.
I looked toward the pool.
Then toward the open patio door.
My first instinct was to protect everyone who might enter the backyard. I shouted through the doorway for anyone inside to remain away from the pool, although I knew the house was currently empty.
Then I raised my phone.
The woman smirked.
"Go ahead. Record me. I don't care."
I looked directly at her.
"You just said you deliberately contaminated my pool."
She shrugged.
"And what are you going to do about it?"
I kept the phone steady.
"You're going to stay away from that water and put the bag down."
She shook the remaining material toward the pool.
A few pale grains fell from the torn corner.
Then she tossed the empty bag onto the patio.
"There. Now call whoever you want."
I looked at the bag.
The blue packaging was printed with white lettering and images suggesting a commercial pool product. I couldn't tell whether the material inside matched the label, whether the packaging had been altered, or whether the woman's claim was simply an attempt to frighten me.
I wasn't going to guess.
The water was now off-limits until professionals established what had been introduced.
I took another step backward.
Then I pressed the emergency call button on my phone.
The woman laughed.
"That's right. Call the police. Tell them you're terrified of a little old lady."
I didn't answer.
Because I knew something she didn't.
The security cameras above my patio and side gate had already recorded her breaking into the property.
And this wasn't the first time the police had been called about her.
The dispatcher answered while the woman continued laughing.
I gave my address, explained that a person prohibited from entering my property had forced open the gate, and reported that she'd deliberately dumped an unidentified substance into my swimming pool while claiming it contained a dangerous organism.