"Explosive" information from Chris Watts' girlfriend helped investigators

The girlfriend of Chris Watts, a Colorado man sentenced to multiple life sentences for the murder of his pregnant wife and two daughters, played a vital role in consolidating investigators' suspicions that he was involved in their disappearance.

"Nichol Kessinger has turned out to have information that I can best describe as being a bomb," said Weld County attorney Michael Rourke in an interview broadcast Sunday at the "Investigation" investigation. Discovery ".

Watts pleaded guilty in November to the murder of his wife Shanann Watts, who was pregnant, and his daughters Bella, 4, and Celeste, 3, who are currently serving three life sentences.

When Shanann, Bella and Celeste disappeared last August, the local media came down, and Watts begged on camera for his family to be fired safely.

For Kessinger, something did not seem right. She had been in love with Watts for two months and she thought the police should know it.

"We started dating quite often in the last week of June," Kessinger told the police, according to recordings broadcast Sunday night.

"He informed me that he had two children, that he was separating from his wife, and as far as I know, it was coming to fruition."

"I wonder if there is more to this story than I know because I think he's a very good guy, and you know, I'm worried about his wife and kids," she said. declared. "And it scares me, these girls are so small, and she's pregnant, you know, and how's their mother?"

Police found that the cards Watts sent to Kessinger, photos of the pair and e-mails exchanged between them, began to focus on Watts, prosecutors told Investigation Discovery.

"It seemed to us that he was definitely planning to start a new life, Shanann and Bella's own and Celeste and Niko with the love of his life – that's how he described Nichol Kessinger" said Rourke. Shanann and Watts had planned to name their third child, Niko.

Watts first acknowledged that he had killed only Shanann. He said he found them strangling their daughters and then strangling him.

But in November, he pleaded guilty to killing the three men, with the goal of avoiding the death penalty.

Watts had previously led the investigators to the property of Anadarko Petroleum, where he worked and had disposed of the bodies. Shanann was found in a shallow pit on the site and the bodies of each of the girls were found submerged in separate oil tanks.

The recovery of the bodies was horrible, the investigators said. "Many different people have had to participate in this, and I do not know if they ever will," said Weld County Attorney General Steve Wrenn.

"We have to have staff at the scene of the crime that goes up in these tanks to recover the bodies of these two little girls," Rourke said. "From a fundamental human reaction, how can you do this to your own children?"

After his conviction, Watts confessed to the investigators during a lengthy interview with the prison that he had killed his entire family. He said that he had first strangled his wife after telling him that he did not like her anymore.

"I have no control over him, why can not I let him go?"

Watts said that he then loaded his daughters and Shanann's body into his truck and drove them to Anadarko, where he had smothered his daughters and got rid of the three bodies.

Elisha Fieldstadt

Elisha Fieldstadt is a late-breaking journalist for NBC News.