A 34-year-old man in Missouri has been arrested for allegedly killing the mother of his child, who was found sitting upright in a chair inside her home with a plastic bag taped over her head. Karl Mayberry was taken into custody on Wednesday and charged with one count of first-degree murder in the 2021 slaying of 31-year-old Alvatyne Thomas, court records reviewed by Law&Crime show.

According to a probable cause affidavit, officers with the St. Louis Metropolitan Police Department on Dec. 27, 2021, responded to a home in the 4000 block of Oregon Avenue regarding a request for a welfare check.

Upon arriving at the scene, first responders said they entered the home and located an adult female, later identified as Thomas, already deceased with “a plastic bag taped around her head.”

“She had been shot in the back and had extreme swelling to her forehead, a severed ear and apparent defensive wounds on her hands,” the affidavit states. “She appeared to have had bleach poured over her body as well.”

During the ensuing investigation, officers said they learned from Thomas’ family that she had been in an abusive relationship with the father of her child, whom they identified as Mayberry. Investigators obtained and executed a search warrant on Thomas’ cellphone.

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The data obtained from her phone allegedly showed that Thomas had been texting with Mayberry shortly before her death. In the text messages, she allegedly told Mayberry that she was at her house and was about to go to sleep.

In an interview with detectives, police said Mayberry claimed that he was at work at the time Thomas was killed.

“However, officers interviewed multiple co-workers, who stated the Defendant had disappeared for hours during the timeframe in question,” the affidavit states. “Officers also learned that, when the Defendant appeared again, he was in different clothes and appeared emotionally distraught.”

A search warrant was obtained for Mayberry’s cellphone as well as his social media. On the phone, authorities said they found messages sent by Mayberry to another unnamed person just after Thomas’ murder. In the messages, Mayberry wrote that Thomas had been “found dead in the kitchen with a plastic bag wrap around her head.”

According to authorities, Mayberry’s message about the details of Thomas’ murder were sent “prior to police releasing this accurate information to anyone.”

In addition to the messages, Mayberry also allegedly performed several incriminating internet searches around the time of Thomas’ death. Those searches allegedly included “first degree murder defenses” and “can he say she say be used against a person for murder in Missouri,” among others.

Mayberry also sent a text message to a criminal defense attorney inquiring how much it would cost “to defend a murder,” according to the affidavit.

Mayberry is currently being held at the St. Louis City Justice Center without bond, jail records show. Court records show he was on federal probation at the time of Thomas’ death due to convictions for assault and being a felon in possession of a firearm.

He made his initial appearance in court on Friday afternoon.