The charges against 23-year-old Reginald Kimbro, the man accused of killing his ex-girlfriend at her TCU-area garage apartment, have been upgraded to capital murder.
Kimbro is accused of fatally strangling 22-year-old Molly Matheson in her apartment.
When Matheson failed to show up for work April 10 and didn't answer her phone, her mother entered her unlocked apartment and found her body curled up on the bathroom floor, partially clothed in only a T-shirt.
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According to an arrest warrant affidavit, Kimbro admitted to detectives that he and Matheson dated while at the University of Arkansas and that they were hanging out at her apartment Friday night, but he said they did not have sex because she said it would upset her boyfriend.
Kimbro said he left Matheson's apartment at about 1:30 a.m. and had nothing to do with her death.
During the investigation, the Tarrant County Medical Examiner's Office determined Matheson died of homicide by strangulation. According to an arrest warrant affidavit, homicide detectives suspected Matheson may have also been sexually assaulted and, upon learning of two previous allegations of sexual assault against Kimbro, ordered a rape kit expedited by the medical examiner.
- Warning: Reginald Kimbro Arrest Warrant Affidavit (contains graphic account of alleged sexual assault)
On Thursday, the murder charge against Kimbro was upgraded to capital murder and his bond amount was raised from $500,000 to $1 million.
The Tarrant County District Attorney's Office said Thursday afternoon the charges against Kimbro were upgraded after finding evidence to support Matheson had been sexually assaulted.
In a search of her apartment, police found a pair of Matheson's running shorts, panties, a pillow case and a fitted sheet in the washing machine, along with a pair of men's underwear, still wet.
Detectives used electricity records to show a spike in power consumption about the time a neighbor’s surveillance camera showed Kimbro’s car leaving the apartment, which police said was 2 a.m. Police believe Kimbro could have loaded and started the washing machine as a means to destroy evidence.
According to an arrest warrant affidavit, Kimbro had been accused of sexual assault twice before -- in Plano in 2012 and at a resort in South Padre in 2014. In the affidavit, police said Kimbro knew both of the women and was accused of strangling them during the assault.
In the 2012 case, Kimbro claimed the sex was consensual and the charges were dismissed. In the 2014 case, prosecutors declined to pursue the case for an unknown reason.
Kimbro remains jailed in the Mansfield Jail. He is scheduled to appear in court on May 19.
NBC 5's Don Peritz and Scott Gordon contributed to this report.