Now, that teenager — Darwin Christopher Bagshaw, who's eighteen today, but was fourteen when the crime was committed — has pleaded guilty to killing her.
Why did he commit this horrible act? Apparently because he thought Kasprzak was pregnant — which she wasn't.
We've incorporated our previous coverage into this post.
As we noted, the murder took place in the Utah community of Riverton.
According to Salt Lake City's Deseret News, 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 noted that a jogger 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. On March 24, Fox13 in Salt Lake reported, 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 blood stains 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 Colorado was announced.
Charging documents obtained by the Deseret News offered more details.
The newspaper revealed 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 the boyfriend had asked him to lie on his behalf. This same pal says the boyfriend 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 the boyfriend'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 cellphone location info allegedly showed that the boyfriend 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, as the Associated Press points out, 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.
Bagshaw's trial was slated to get underway on Monday, March 7.
But earlier this week, he pleaded guilty to the killing.
At his sentencing hearing, set for April 25, he could receive a minimum of fifteen years behind bars.
We offer our sincere condolences to the friends, family and loved ones of Anne Kasprzak. Look below to see a KUTV report.