Attorney for Waukesha Man Charged With Homicide Apparently Planning Self-Defense Case

Waukesha County prosecutors intend to present evidence at an upcoming homicide trial that Steven P. Osburn was in an agitated mood on the night he is accused of fatally shooting a Marines veteran, going back 11 hours before Gallenberg’s death to when Osburn was given divorce papers.

Meanwhile, Osburn's attorney, Gerald Boyle, appears to be pursuing a self-defense claim by his statements in court. Boyle said in court he plans to put Osburn on the witness stand during an upcoming trial.

The circumstances the night Gallenberg was killed showed the totality of the situation were Osburn was “a very angry, short tempered person who is confronting others, threatening others and drinking to excess," Waukesha County Assistant District Attorney Stephen Centinario argued in court Tuesday afternoon.

Osburn, 25, of Waukesha, an Army veteran who is accused of killing his friend, 23-year-old Zachary S. Gallenberg, in a south Waukesha neighborhood on Aug. 6, 2010, is charged with first-degree intentional homicide, strangulation and suffocation, intimidating a victim/threaten force and intentionally point firearm at person.

Boyle, who originally was seeking a special not guilty plea due to mental illness, told Waukesha County Judge Mark Gundrum Tuesday afternoon that he would not pursue a post traumatic stress disorder defense. Boyle previously withdrew the special not guilty plea.

However, Boyle did ask Gundrum to not allow prosecutors to present evidence that Osburn’s wife had asked for a divorce and informed him she planned to file for divorce the following Monday. He also wanted the judge to prohibit testimony that Osburn was allegedly involved in two altercations at a bar the night of the shooting.

“In this particular circumstance, the state is using the alleged acts as inferences, which is forbidden under the statutes,” said defense attorney K. Richard Wells, who is working with Boyle on the case.

Gundrum is allowing prosecutors to bring up the events in the 11 hours before Gallenberg was shot and said the information shows a framework and gives the jury a look at Osburn’s state of mind after receiving the divorce papers.

“It provides context,” Gundrum said.

A witness to the shooting told Waukesha Police Department officers that she, Gallenberg and Osburn had consumed some alcohol during the night of Aug. 5. Osburn and Gallenberg were arguing about their different branches of the military throughout the night, according to the criminal complaint filed in Waukesha County Circuit Court.

The woman told investigators at one point in the evening, Osburn began choking her before going into his bedroom and then outside. Gallenberg eventually followed, she told police, and tried to give Osburn a bear hug, which is when Osburn took out a gun and shot Gallenberg, the complaint states.

In the meantime, police officers responded to the residence because Osburn called 911 and said if they did not respond, he would kill someone. One of the officers was approaching the residence when he heard the gunshot sound. Other officers were approaching the building at the same time. One officer reported turning the corner of the building, seeing Osburn, hearing yelling and then seeing the muzzle flash, according to the complaint

Osburn admitted several times to officers that he had shot Gallenberg, the complaint states. Gallenberg was transported to Waukesha Memorial Hospital where he was pronounced deceased at 4:47 a.m. Aug. 6.

“It bothers me that I shot Zach because he was my best friend, but I was threatened,” Osburn told police, according to the complaint.

Boyle also told Gundrum that Osburn did not challenge the confession that he gave to police officers that night. Gundrum asked Osburn a series of questions, to which Osburn quietly answered while sitting next to Boyle, wearing a short-sleeved orange Waukesha County Jail jumpsuit.

The jury trial is scheduled to begin at 8:30 a.m. June 6. The trial will start with jury selection, which is set to have a pool of 60 potential jurors. A jury status hearing will be held at 10:30 a.m. June 2.