Out for a Sunday morning run along the Jordan River in Utah, a jogger makes a grisly discovery: Blood pooled at the foot of a bridge, and close by, a single show.

A helicopter search over the area yields a figure in the river. On March 11, 2012, Police arrive on scene and pull a female body out of the water, beaten beyond recognition. On her foot, the matching shoe.

Crime Watch Daily Salt Lake City affiliate KSTU reports that just the night before a desperate mother discovered that her daughter Annie was missing.

Veronica Kasprzak says that a family argument may have prompted her 15-year-old daughter to leave the house. But when Veronica saw news reports that a body was found near the river, she had a chilling premonition that it was Annie.

But who would viciously and brutally beat this pretty teenager to death? Annie's family is desperate for answers.

Police mount a massive search for the killer, including questioning Annie's boyfriend Darwin Bagshaw. Police soon arrest two other men: Veanuia Vehekite and Daniel Ferry. Annie's family has doubts about their involvement.

Court documents say a witness claimed the two men assaulted and murdered Annie after a party when she allegedly refused Ferry's sexual advances.

At a hearing, Ferry maintained his innocence, claiming a drug addict was angry with him and made up the whole story. The two men were soon released and were never charged with the murder.

Then a break: After two years, a tip points in the direction of Grand Junction, Colorado, where police focus back on Annie's ex-boyfriend, Darwin Bagshaw. Detectives discover a number of calls made between Annie and Bagshaw on the night she disappeared. The calls ended around 8:30 p.m.

They also discovered blood on the Bagshaw's shoes. Initially, Bagshaw explained the droplets away, saying Annie had a bloody nose. But a friend who initially confirmed Bagshaw's story later admitted he lied to police.

Bagshaw, 17, is arrested and extradited to Utah, charged with first-degree felony murder and obstruction of justice.

"We looked at everything in every avenue and with everything that we have, we are confident that we have the suspect in custody for Annie's murder," said Draper, Utah Police Chief Bryan Roberts.

"It feels incomplete to say that it is any sort of a relief, because it does not change what happened," said Annie's mother Veronica Kasprzak.

Police records say on that dark night, Annie and Bagshaw met up by the river, where allegedly Annie told her 14-year-old boyfriend she was pregnant with his baby.

The records reveal that after hearing the news, an enraged Bagshaw lost his temper and beat her to death with a shovel, then dumped her body in the water.

"The injuries and everything that she suffered and went through, it was unimaginable that somebody could do that to somebody else," said Veronica Kasprzak.

Annie, 15, died from blunt force trauma to the head.

KSTU reports that an autopsy later revealed a stunner: Annie was never pregnant. Her family wonders if it was only an attention-seeking ploy.

Darwin Bagshaw pleaded guilty in court, standing before a judge, admitting to beating, killing and then dumping the body of Annie Kasprzak in the river.

But even with a guilty plea, Annie's family is furious that for more than two years, while police feverishly investigated Annie's murder, Bagshaw was living his life under the radar in Colorado.

At the sentencing Annie's family spoke to their daughter's killer.

"May you feel sadness, may you feel loss, may your tears heal your soul," said Veronica Kasprzak.

Darwin Bagshaw addressed Annie's family.

"I'm very sorry for everything that's happened, and I want to apologize to Annie's family and to my family and to everybody in court today for putting everybody through this," Bagshaw said.

The defense argued that since Bagshaw was just 14 when he committed the crime, he should be sentenced as a juvenile. The judge disagreed, sentencing him as an adult.

"A terrible crime deserves a serious sentence and here we have about the worst crime that one can possibly imagine," said Judge James Blanch.

Darwin Bagshaw will now spend the next 15 years to life in prison. Little consolation for the Kasprzak family, who have lost their precious Annie forever.