Teen Darwin Bagshaw's Murder of GF Who Faked Pregnancy Hits Dateline

Of late, Dateline NBC has shown a strong interest in crimes connected to Colorado.

Just a few weeks ago, Dateline featured the case of Ralph Candelario, a Walsenburg resident who was convicted of murdering his wife, Pam, then staging the scene to make it look as if she'd been killed by intruders.

Candelario's first wife, Dena Candelario, has been missing since 2004 — and after the broadcast, the investigation into Dena's disappearance was reopened.

Tonight, Dateline takes on another story we've covered in this space: the tale of Darwin Bagshaw, who pleaded guilty to killing his girlfriend, Anne Kasprzak, when she was fifteen and he was fourteen.

A preview from the program, titled "The Girl With the Red Shoes," is on view below.

Bagshaw's motive? Prosecutors said Kasprzak told Bagshaw that she was pregnant even though she wasn't — and he reacted by beating her to death.

The murder actually took place in the Utah community of Riverton — but Bagshaw was living in Grand Junction at the time of his arrest, well after the original crime took place.

As we've reported, Kasprzak, then a freshman at Summit Academy in the town of Draper, was reported missing by her parents on March 10, 2012.

At about 10:30 a.m. the next day, the Draper, Utah, police department learned that a jogger had noticed blood and a shoe on a pedestrian bridge over the Jordan River.

Officers were soon dispatched to the scene, with a helicopter eventually joining the search — and before long, a body was spotted downstream in the river.

It was Kasprzak.

An autopsy determined that she'd died as a result of multiple blunt-force injuries to her head.

At first the investigation seemed to move quickly. By March 24, local police had issued a probable-cause statement aimed at two men in their thirties.

According to that document, a witness claimed Kasprzak had been assaulted during a party at one of the men's homes, after which she was wrapped in a tarp and taken away while still alive.

This pair and another unidentified man were said to have returned hours later with bloodstains on their clothing.

The two men were promptly arrested.

However, one was never charged, and the following year, law enforcers confirmed that the other was no longer considered a suspect.

At that point, the inquiry seemed to stall, only to flare to life again via a news conference on October 16, 2014, at which the arrest in Grand Junction was announced.

Charging documents offered more details.

The reports documented that a number of calls were made between Kasprzak and her boyfriend — later identified as Bagshaw — on the evening she disappeared.

The exchanges ended sometime after 8:30 p.m.

After the body was identified as Kasprzak, cops reportedly quizzed the boyfriend — and they found blood on his shoes.

He explained that Kasprzak had suffered a bloody nose two weeks earlier, resulting in the spatter — but a friend who initially confirmed this story later told investigators that Bagshaw had asked him to lie on his behalf. This same pal says Bagshaw admitted he'd been to the Jordan River the evening Kasprzak disappeared but asked him to keep that to himself, as well as to erase some text messages.

Other evidence is said to have included a shredded piece of paper found in Bagshaw's trash can that featured a "rough timeline" of what happened and mention of a jacket like the one Kasprzak had been wearing on the night in question.

And cell-phone location info allegedly showed that Bagshaw had chatted with Kasprzak's concerned mom when he was about 100 meters from the crime scene.

In the beginning, Bagshaw wasn't identified owing to his age, and the case against him originally moved forward in juvenile court.

However, prosecutors argued for Bagshaw to be tried as an adult, and a judge ultimately agreed.

This shift in approach led to the release of more details about what may have led to Kasprzak's murder.

Prosecutors say she told friends she was pregnant — something that apparently distressed Bagshaw.

Shortly thereafter, Kasprzak was killed — and a postmortem examination revealed that she wasn't actually pregnant after all.

Bagshaw's trial was slated to start on Monday, March 7.

But mere days before the proceedings were expected to get under way, he pleaded guilty to the killing — and on April 25, he was sentenced to a term of between fifteen years and life.

Here's a preview of tonight's Dateline episode.