HAYWARD -- Closing statements will begin next week in the murder trial of Cort Holbrook, a Livermore software engineer charged with a fatal stabbing during a March 2011 road rage incident.

Ricky Ziesmer, 48, of Fremont, was stabbed in the altercation with Holbrook, who has said it was self-defense after Ziesmer beat him to the ground, kicked him while he was down, and then came back at him for a final punch.

In Alameda County Superior Court on Thursday, the prosecutor alleged that the March 9, 2011, stabbing was not an act of self-defense, but rather an act of revenge on the man who Holbrook said charged his car as he pulled over to call 911 on the reportedly erratic Ziesmer.

Holbrook admitted to flipping Ziesmer off and cursing at him through his open window after the man cut him off in traffic multiple times, and confessed that he regretted making contact with him in the first place.

"You were so mad that he assaulted you that you stabbed him as he was turning to get away from you, is that right?" deputy district attorney Brian Owens said.

Holbrook repeatedly denied these allegations, insisting to the court that he was only trying to protect himself from Ziesmer's repeated attacks.

"I did not want to kill anybody," Holbrook said. "I was defending myself and my life. That's all I cared about."

According to the testimony of Holbrook, 43, he felt threatened for his safety after an "inconsolable" Ziesmer charged toward him and said "I have no problem putting you down, (expletive)."

Ziesmer then reportedly punched Holbrook twice in the head, knocking him to the ground and sending his glasses flying.

Owens showed the jury the push dagger used to stab Ziesmer after this attack, noting that the knife Holbrook claimed he bought on impulse with candy and soda in a liquor store six years ago is the best on the market, advertised as being "even better than firearms."

Holbrook stabbed Ziesmer twice in the torso with the dagger, then slashed his back rear tire to keep him from leaving the scene.

Ziesmer then got in the disabled vehicle and drove to Valley Care Medical Center, where he later died in surgery.

Forensic toxicologist Jeffery Zehnder testified Wednesday that the .02 blood alcohol content found in Ziesmer's body after he died was likely much higher during the incident, before his significant blood loss and blood transfusions, approximating his blood alcohol content during the incident at about 0.12.

No drugs or alcohol were found in Holbrook's system on the day of the incident. Only a mild antidepressant was found in his bloodstream.

Both sides will finish their presentations Monday at the Hayward Hall of Justice. Holbrook remains at Santa Rita Jail on $3 million bail.

Contact Erin Ivie at eivie@bayareanewsgroup.com. Follow her at Twitter.com/erin_ivie.