My 12-year-old son spent his summer mowing lawns for elderly neighbors for free — after his last job of the summer, two police cars pulled up outside our house, and what happened next made my hands start shaking.

Have you ever gone from being incredibly proud of your kid to absolutely terrified for them in a matter of seconds?

That's pretty much what happened to me recently.

My son, Justin, is 12, and I swear he has one of the biggest hearts of any kid I know.

I never told him to spend his summer helping people.

He came up with that completely on his own.

A few days into summer break, Justin saw an elderly neighbor struggling to mow her lawn in the heat.

He went over, finished it for her, and refused the money she offered him.

Afterward, he came home and said, "Mom, there are probably other people around here who need help too."

And that became his summer thing.

Since he didn't have school to worry about, he'd spend a couple of mornings each week pushing our old mower around the neighborhood and helping elderly people who couldn't easily take care of their yards themselves.

He never took a dime.

Honestly, I couldn't have been prouder.

Justin isn't some perfect kid, but watching him spend part of his vacation helping people without expecting anything in return made me realize what a genuinely good person he was becoming.

Then, right before school started, Justin went out to mow one last lawn.

He came home about an hour later, and everything seemed normal.

Until two police cars pulled up outside our house.

My heart dropped.

Two officers stepped out, both looking dead serious, and walked straight to our front door.

When I opened it, one of them asked, "Ma'am, is your son the boy who's been mowing lawns for some people around the neighborhood?"

I had absolutely no idea what was going on.

"Yes.

Why?

What happened?"

I called for my son, and when Justin walked into the room, the officers' attention immediately shifted to him.

And what happened next made my hands start shaking.