Many of us are already planning our New Year's resolutions to work out more in 2023.

But let's face it, they rarely stick.

Well, Peloton's got a gift for you.

Get up to $200 off accessories, like non-slip-grip dumbbells, cycling shoes,

heart remonitors, and more, with the purchase of a Peloton bike, bike plus, or tread.

Don't wait. Get this offer before it ends on December 25th.

Visit 1Peloton.com. All Access Membership Separate Offer ends December 25th.

Cannot be combined with other offers. See additional terms at 1Peloton.com.

On a bitterly cold Tuesday in January 2015, the home of Harold and Sarah Knight is quiet and dark.

Located in Fenville, Michigan, the house sits on a rural road about 20 miles from the blustery shores of Lake Michigan.

Inside, the furnace has been turned off, and it's so cold the water in the toilet has frozen over.

In the living room, there's a sheet draped across the middle of the floor,

and underneath it is a shocking sight.

The icy corpse of 48-year-old Sarah Knight. She's been strangled to death.

I'm Steve French, and this is Unsolved Mysteries, 9-1-1 Confession.

That day, I remember it because it was so bitterly cold.

It was one of those days that if you're standing outside, I mean, you felt that your ears were burning,

your fingers. I mean, you couldn't stand more than a couple of minutes outside.

You had to, you know, get some place and get warm.

At the time of the unusual 9-1-1 call on January 13, 2015, Craig Gardner is a veteran case detective with the Alligan County Sheriff's Department.

I was sitting in the office, and we received a call from our central dispatch saying that they got an anonymous call to this batch center,

and the caller stated that he had killed her, he had strangled her, and she is dead, and that she's laying on the living room floor,

...