ST. PETERS, Mo. (NewsNation Now) — An O’Fallon, Missouri man has been charged with murder for the Thanksgiving Day fatal stabbing of 22-year-old Amethyst Killian and her unborn baby.

Damion Delgado has also been charged with armed criminal action and second-degree murder for the death of Killian’s unborn child.

“It was a very violent, violent killing,” said Tim Lohmar, St. Charles Prosecuting attorney during an afternoon press briefing.

Lohmar said Killian was stabbed more than 20 times, mostly in the head, neck, and abdomen. He said a motive is not clear and Delgado hasn’t shared what led to the murder.

Lohmar said Killian and Delgado met online and were engaging in some dangerous activity the night of the crime, but wouldn’t go into more detail.

The prosecuting attorney said investigators were told Killian left her house in the early morning hours of Nov. 26 to go buy cigarettes.

Her boyfriend and step-father went to search for her when she didn’t return. Lohmar said about 20 hours after her disappearance, they found Killian’s purse and some of her clothes near her home.

Her relatives contacted police and not long after they arrived they found her body in a brush.

Lohmar credited outstanding police work to crack this case. He said more than two dozen investigators worked around the clock.

“It is textbook definition of good police work,” said Lohmar.

Lohmar said several droplets of blood were found on a knife, sidewalk, and fence near the scene. It came back to an unknown male that was later identified as belonging to Delgado.

Investigators also discovered the victim was communicating with Delgado on the Text Now app.

Officials got a subpoena for her phone records and were able to connect that Killian’s last communication was with Delgado.

Investigators got an IP address from those texts and were able to trace it to a residence where Delgado was staying.

Lohmar said the biggest breakthrough was when a piece of evidence they found at the crime scene was identified in one of those text messages. The defendant allegedly admitted to purchasing the item, which police did not disclose.

Lohmar said detectives then went to several gas stations in the area and pulled records to see if a similar item was purchased.

He said Delgado was seen on surveillance video 10 to 15 minutes before he met up with Killian at a local gas station.

Detectives also interviewed the Uber driver who allegedly drove Delgado to the scene.

Lohmar said Delgado, who is being held on a $1 million bond, has little criminal history.

NewsNation affiliate KTVI contributed to this report.