Inspector Franz Helmcke had a problem. He had caught a new case and had very little to do. Kassannidra Cantrell, 33, had disappeared from her mother’s home near Tacoma, Wash., and none of her relatives – her twin brother Rob, her mother Marie Smith and her closest friend Alexandra McNary – were missing. had the slightest idea of her. Or.
Once upon a time, Kassannidra’s demise may have turned into a cold case, but these days digital breadcrumbs are everywhere. And the same goes for cameras, as her heartbroken mother, Marie, pointed out: “The world is so wired, you know, with cameras. So many people have Ring cameras…so many companies…it’s just impossible that someone hasn’t seen something. “
Detective Helmcke was only too aware of this, and he also knew how to tap into all the digital material that is ubiquitous in our daily lives. Over the course of a month in 2020, he and his fellow investigators used cellphone recordings, deleted texts, vehicle location data, store receipts, surveillance videos and even an underwater net to find Kassannidra Cantrell’s remains and build what they believe to be a strong homicide case against her ex-boyfriend Colin Dudley.
The full story of this successful digital investigation is the subject of an all-new “48 Hours” reported by contributor Natalie Morales. “Kassanndra’s Secret,” airing Saturday, April 8, 2023 at 10/9c on CBS and streaming on Paramount+.
Helmcke and his fellow investigators were unable to identify a murder weapon, never located eyewitnesses or obtained a confession. Yet they were able to create a compelling digital dossier that apparently tracked Dudley’s every move as he attempted to cover up his crime.
The trail of evidence began the same day Kassannidra went missing. Helmcke surveyed his neighborhood and spotted a neighbor’s security camera. That camera provided the first clue – a quick video clip of Kassannidra’s white Mazda driving away from her mother’s house at 8:25 a.m. on August 25, 2020. There was no video of the car returning.
Helmcke also ordered that an emergency trace be placed on Kassannidra’s cellphone for her last known location. He showed that his phone last rang about two miles south of a cell tower on an island in Puget Sound.
“One of the first things I did was go to Google Earth and create an arc from this tower to see where it lands,” Helmcke told Morales. “It showed that he was landing…around this shoreline at Owen Beach [in] Point Defiance Park.
A few days later, the Pierce County Metro Dive Team led by Det. sergeant. Brent Van Dyke gathered in Owen Beach on a busy summer day. Puget Sound is nearly 100 miles long, but at least they knew Kassannidra’s cell phone had probably been dumped in the water from Owen Beach.
Thanks to a low tide and some ingenious guesswork, the dive team found Kassanndra’s cellphone in the water after just over an hour when a team member spotted the spark of the Kassanndra phone case. The phone was sent to a specialist to see if any information could be recovered.
But even without this information, Det. Ryan Salmon, the cellphone forensics specialist for the Pierce County Sheriff’s Department, used phone company records to see when and where Kassandra and Dudley interacted. And later they found text messages from Dudley’s phone that revealed she was meeting her former boyfriend at his house the morning of his disappearance.
“She said, ‘I’m a little early, are you okay? ‘” the detective said. Salmon.
” And he says ? Morales asked.
“He says, ‘yup, get off.’ And those two messages were both deleted from his phone,” Salmon replied.
“And so, the two phones are then located in the same place in the house for a few hours?” Morales asked.
“Okay,” said the detective.
Detectives were in possession of Dudley’s phone at the time and could see that he had deleted these two texts. They also determined that Kassannidra and Dudley had been in regular contact in the months leading up to her disappearance. When asked about her, Dudley told Helmcke that he hadn’t spoken to Kassannidra in years.
Knowing that Dudley was lying to him, the detective began to watch his movements carefully. Dudley said he visited a Costco the morning of Kassannidra’s disappearance, so Helmcke assigned the store receipts and discovered that Dudley had bought a box of heavy trash bags around 7 a.m. The store provided a video of Dudley shopping for these bags.
The investigation was progressing on several fronts. Police had located Kassannidra’s white Mazda with the keys inside on a street near downtown Tacoma. The location was close to the city’s light rail system, so Helmcke asked security staff if they could find video of the car. Their cameras showed a burly man wearing a black fedora walking away from Kassannidra’s car the day she disappeared.
Helmcke had interviewed Dudley in person and was certain from the gait and build of the man he was looking at that it was Colin Dudley. She was also told that Dudley often wore a fedora and liked to be called “Hat” or “Hat Man”.
Helmcke watched as cameras caught the man in the hat entering the Tacoma Dome station parking lot around 11:40 a.m. that morning. He is then seen on the garage cameras getting into a truck and driving off. In one shot, the truck’s license plate is visible and investigators determined it belonged to Dudley. He and the “Hat Man” were one and the same.
Dudley apparently carried Kassannidra’s cellphone with him as he left the garage because his phone records show he was moving towards Owen Beach where investigators believe Dudley dumped him in Puget Sound around 12:45 p.m. on August 25 .
At this time, investigators still did not know where Kassannidra’s body was, so they raided Dudley’s house. They seized several items, including a black fedora and Dudley’s Chevy Colorado truck. But, after providing his fingerprints and DNA, Dudley was free to go.
“Why can’t you stop him?” Morales asked Helmcke.
“Well…he’s guilty of something. But what is he guilty of? he has answered.
It was then that Helmcke again relied on digital forensics. He said he knows that almost all modern cars and trucks have computers that contain tons of information that can be extracted. Detectives pulled the so-called black box from Dudley’s Chevy truck and sent it for analysis.
A company specializing in the extraction of this data sent it back to Helmcke on a USB key. Once uploaded, the data showed that Dudley’s truck drove very early in the morning of August 26 – the day after Kassannidra visited his home – into a wooded ravine. Investigators rushed to the scene where they found Kassannidra’s remains in and around a trash can.
In November 2022, Colin Dudley pleaded guilty to first degree murder and was sentenced to 26 years in prison.