Marty Singer, Kardashian and Thompson's lawyer, sent a cease and desist letter to Kimberly Alexander, the woman claiming to be the mother of Tristan's child.
In it, Singer wrote, "We demand that you immediately stop defaming them with malicious defamatory lies and specious fabrications."
According to the letter, Thompson already took a paternity test for the child that proved he was not the father. Alexander, however, has continued to claim that Thompson is the father--even accusing the NBA player of faking the test.
The letter continues, "After it was indisputably established by a paternity test performed by one of the most reputable labs that Mr. Thompson is not your child's father, we thought that would be the end of this. Instead, you have continued to spread outrageous lies about my clients, including ridiculous fictional conspiracy theories that you conjured up claiming that my clients supposedly somehow falsified the paternity test results since members of the Kardashian family had previously used the same trustworthy lab."
Alexander has not only accused Thompson of being a "deadbeat dad," but also accused the reality star of paying people off to hide the truth.
The letter demands that Alexander stop posting about it on social media (and that she delete previous defamatory posts): "We demand that you immediately cease and desist from defaming my clients on social media (irrespective of whether or not the accounts are public or designated as 'private') and elsewhere. We also demand that you immediately take down any and all of your outrageous damaging posts about my clients."
Singer's letter also points to Alexander's ulterior motives, "It is obvious that the reason you are spreading these lies about my clients is because you want your 15 minutes of fame."
However, Alexander has stood by her story. Speaking to E! News, she explained, "I feel like the whole issue originally stemmed from Tristan not wanting to choose a neutral setting for the DNA testing and using a Kardashian associated DNA Testing facility. I feel as if you really have nothing to hide then why not just go to a neutral testing site. And we both know what happened and exactly what went on between us, that's all I can say for now."