PORTSMOUTH, Va. (WVEC) -- Ex-Portsmouth police officer Stephen Rankin is in court, fighting to overturn his voluntary manslaughter conviction.

Rankin was sentenced to two and a half years in prison last year. He fatally shot 18-year-old William Chapman in a Walmart parking lot in 2015.

Before his attorneys can argue his appeal, they had to convince a three-judge panel from the Virginia Court of Appeals to take up his case.

In court Tuesday, attorney James Broccoletti, discussed points he said should have been heard by jurors. One of the big ones was an expert was unable to testify during the trial.

Broccoletti said one of the reasons why he was not allowed to testify is because he wasn't qualified as an expert in Virginia. Broccoletti argued that the expert was a professional, and could have provided support to Rankin's choices he made that night.

Another big key point Broccoletti discussed in front of the three panel judges was juror tampering. Broccoletti claimed that in courthouse video, you can see a juror and someone else walking around, talking. He said it was during deliberations, and that it needed to be addressed.

Now the next step is a waiting game: it will take around two weeks to a month for a decision on whether there will be an appeal.