Published: Apr 25, 2012 11:31 PM EDT
Updated: Apr 26, 2012 6:31 AM EDT

CINCINNATI (AP) - Former Bengals linebacker Nate Webster was convicted Wednesday of sex-related charges involving the teenage daughter of a former assistant coach for the Cincinnati team.

A jury in Cincinnati found Webster, 34, guilty of four counts of unlawful sexual conduct with a minor. Jurors found him not guilty of three other charges: gross sexual imposition, sexual battery and a fifth count of unlawful sexual conduct with a minor. The jury deliberated for about six hours before reaching the verdict.

Prosecutors say Webster had sexual contact with the girl in 2009 when she was 15 and threatened to harm her if she told anyone. Webster admits having sex with the girl the next year, when she was 16, the legal age of consent in Ohio, but denies that the sexual relations began earlier than that.

Webster was taken into custody after the verdict.

"We obviously are disappointed with the verdict in some respects," Webster's attorney, Gregory Samms said after court. He said they plan to file an appeal after sentencing, but said he could not comment on specific issues being considered for the appeal.

Samms said that the girl lied when she said she was 15 at the time she and Webster began having sex. Prosecutors said Webster told police that he had sex with the girl when she was 15 and played tapes of those interviews in court, but Samms said Webster was mistaken about the dates in his earlier statements.

Assistant Hamilton County Prosecutor Seth Tieger declined to comment on the verdict or other aspects of the case prior to sentencing, scheduled for June 6.

The prosecutor's office said Webster could be sentenced to up to 20 years in prison. Webster could have faced up to 36½ years in prison if he had been convicted on all counts.

The former Bengals player turned down a proposed plea deal prior to the trial that would have required him to serve four years in prison, a prosecutor's spokesman said.

Webster played for the Tampa Bay Buccaneers from 2000-03 and for the Bengals in 2004-05. He finished his career with the Denver Broncos from 2006-08.