Police in Mansfield, Texas, said Boykin is under investigation for aggravated assault resulting in serious bodily injury and that the victim had a prior relationship with him.
The ongoing probe was first reported by WFAA-TV in Dallas after they interviewed Boykin's former girlfriend about the incident. Shabrika Bailey accused the former TCU quarterback of breaking her jaw in two places during an argument over a text message last week. Bailey accused Boykin of choking her until she passed out before she woke up in puddle of blood on the floor. She said hours later Boykin drove her to a local hospital, where she was released three days later.
"I understand the Seahawks decision to release me," Boykin said in a statement obtained by NFL Network Insider Ian Rapoport. "The story that was reported casts a bad light on the organization and on me. I want to be clear that the story is false. The police have taken statements from the accuser, another witness and me. All of these statements confirm that I was not involved in the physical altercation. This woman has lied about me and it has cost me my job. I know guilt by association is real. This person has fabricated a story and I am suffering the consequences. I will let the legal system run its course and I know I will be vindicated."
Seattle cut Boykin hours after the allegations were made public. Boykin hasn't been arrested or charged. He is subject to potential NFL discipline under the league's personal conduct policy regardless of whether or not he is charged.
The former TCU quarterback has been arrested multiple times since leaving college. He was arrested on suspicion of misdemeanor public intoxication and marijuana possession after he was a passenger in a car crash that injured several people in Dallas last March. That arrest led to another arrest in April 2017 for violation of the terms of his probation.
He was sentenced to probation in June 2016 following his arrest in December 2015 on misdemeanor assault and resisting arrest charges for allegedly striking a patrol officer after a bar fight. Boykin pleaded no contest to the resisting arrest charge and avoided jail time.
Boykin, 24, has appeared in five games with the Seahawks since joining the team as an undrafted free agent in 2016.