AceShowbiz -

Mariah Yeater, the 20-year-old who said that she had sex with Justin Bieber, is making the pop singer's life more complicated. She reportedly won't take down her claim that her four-month-old baby is Bieber's, demanding the singer to take another DNA test.

Bieber agreed to take paternity test last Friday, November 18 because he wanted everything to be out in the open. Although the test was reportedly taken under "very controlled circumstances", Yeater's attorney Jeffrey Leving told E! News that they want to be present when the do-over test is conducted, so that they can confirm that the sample is truly that of the 17-year-old.

"We have been negotiating a DNA test," Leving said. "We just received communication from Justin Bieber's lawyer today concerning our discussions, which are private. We are trying to set up a DNA test-to test the mother and the child and to retest Justin Bieber. Because we have to make sure the chain of custody is properly supervised."

On why he wants the do-over, Leving said, "I wasn't aware Justin Bieber was allegedly taking a DNA test until I read about it. I don't know if it was even his DNA. Evidence has to be properly supervised to make sure it is not corrupted. What I am hoping is to get DNA testing done for everybody and to have it done in a supervised setting."

Leving also said that Yeater will submit her baby's DNA for testing, in fact she "can't wait". The attorney added, "We are trying to do this outside of court. If it can't be done out of court, then the only other option is to refile."

Bieber and his team have vowed to pursue legal actions against Yeater and her new attorneys when the test shows that he is not the father.