TULSA, Oklahoma - The defense team in the manslaughter trial of former Tulsa County Reserve Deputy Bob Bates presented its case Tuesday in court. Bates is accused of accidentally shooting Eric Harris during an undercover sting. Bates said he pulled his gun instead of his Taser by mistake. 

He has pleaded not guilty to second-degree manslaughter. Bates will not testify in his own defense.

Bates' attorney says Bates gave a statement last April and it was the facts and that remains the same today.

The prosecution plans to call two rebuttal witnesses, an emergency room doctor and cardiologist, to disagree with defense experts that a heart attack - not a bullet - caused Harris' death.

Tuesday morning, trauma expert Dr. Mark Brandenburg testified that the medical examiner made a couple "huge mistakes" in saying that Eric Harris died from blood loss and collapsed lungs.

Brandenburg said the ME's opinion goes against what the doctors at St.John noted in their reports. He said they reported no blood in his lung or sack around the heart. He says what the ME was seeing was the result of the medical work that was done to save Harris - the opening of the left chest, the insertion of a chest tube and other procedures. 

The trauma expert testified that Harris had an underlying heart condition and likely had a heart attack that was not caused by the gunshot wound. The expert witness said despite the doctors at St. John doing heroic measures to try to save his life, Harris was likely dead when the ambulance pulled up to the hospital.

He also testified that meth use and long-term high blood pressure attributed to Harris' health problems.

After a break, the expert was cross-examined by the prosecution. He admitted he is charging $300 to $400 an hour for his researching and testimony. He said he's already billed Bob Bates' attorneys $5,000 for the work he did in March. He hasn't billed yet for April.

The prosecutor asked why Harris didn't die of a heart attack days before when he was also on meth, under stress and exerting himself by riding a bicycle. Why did it happen on the day he ran and was shot?

The trauma expert said it was just that specific combination of factors that day, April 2, that caused the heart attack.

The judge also said he is watching the weather and will make sure to get the jury out of the courtroom so they are safe. They are taking a shorter lunch break in case they have to stop the trial early.

The jury is expected to hear closing arguments on Wednesday before deliberations.