Hunting a predator

Denver-area detectives knew they were up against the clock to catch a serial rapist before he attacked again. "48 Hours" goes deep into the race to catch him  in "Hunted."

On Jan. 5, 2011 Golden, Colorado, Detective Stacy Galbraith was just starting her shift when a call came in about a sexual assault. Galbraith quickly responded to the apartment of the 29-year-old woman, who said that she had been in bed when a masked man came into her room.

The masked man

The victim said that the masked man straddled her, threatened to shoot her with a gun he had brought, then photographed her during the assault, and threatened to share the images online if she went to police.

Washing away the evidence

The attacker then made the victim go into the bathroom and shower for a set period of time – using soap – while he packed up her sheets, clothing, and anything else that could have contained his DNA. He then left.

A distinct birthmark

Detective Galbraith had little to go on at the crime scene in Golden, but she did have her victim's description of the attacker from what she could see – he was a white male, about six feet two inches tall, with light colored hair on his arms. And she sketched this distinctive egg-shaped birthmark on his right calf.

Searching for a clue

But the only solid piece of physical evidence that Det. Galbraith had to go on was this Adidas shoeprint in the snow outside the Golden, Colo., victim's apartment building.

Another case

Detective Galbraith went home that night and mentioned the case to her husband, a police officer in the nearby town of Westminster, Colo. He remembered an open case that was very similar. He connected her with the Westminster detective in charge of that case, Edna Hendershot.

An unmistakable connection

As Detectives Galbraith and Hendershot compared notes, one detail stuck out. "My victim had a pink Sony Cyber-shot camera that was stolen from her," said Hendershot. Galbraith immediately replied, "My victim was photographed with a pink Sony Cyber-shot camera."

Not quite a fingerprint

At the scene of Detective Hendershot's case in Westminster, the attacker had also been careful to leave little evidence, but investigators identified this unique honeycomb pattern on a railing outside of her apartment. "Definitely not a fingerprint… But impressions from a glove," said Hendershot.

The list grows

By early 2011, the investigation into the Westminster case been open for months, and Det. Hendershot had already connected another case to the same suspect – this 65-year-old grandmother, who we call "Mary," had suffered almost exactly the same attack back in 2009, but there had been few leads.

A partial DNA profile

Again, there was little evidence left at the scene of Mary's attack, but she had remembered that the attacker had touched this teddy bear in her home during the attack, and he forgot to remove it when he left. The Westminster investigators had been able to lift a partial DNA profile from the bear.

The clock is ticking

The detectives now knew of three cases in the last two years, all by the same dangerous attacker, and were sure that he would strike again. They formed a task force with law enforcement agencies around the Denver area – including FBI Special Agent Jonny Grusing – to track him down.

New case links others

Agent Grusing scoured the area for signs of the attacker and came across a case in Lakewood, Colo., that seemed to fit his pattern -- except that it had been classified as a home invasion. But Grusing saw that it was actually a failed rape attempt, and this time the attacker had left gloveprints and shoeprints that tied it to each of the other attacks.

The white truck

But the most significant find from the Lakewood attack was this photograph of a white pickup truck seen near the scene. When an analyst mentioned it at the end of a long task force meeting, Det. Galbraith keyed in – she had seen the exact truck in surveillance video near the Golden scene. However, this time, they were able to read the license plate.

Hunting the hunter

After just a few weeks, Detectives Galbraith, left,and Hendershot now had a solid lead on the man they believed had committed a series of violent rapes, The hunter was about to become the hunted.

For more, watch "48 Hours: Hunted"