The Deputy King County prosecutor who has been trying for more than two months to convict Conner Schierman of brutally murdering a Kirkland family said Thursday that the 28-year-old is “guilty beyond all reasonable doubt.”

Now the jury is moving into deliberations.

Schierman is accused of killing Olga Milkin, 28, of Kirkland; her sons, Justin, 5 and Andrew, 3; and her sister, Lyubov Botvina, 24, who were stabbed multiple times before their bodies were drenched with gasoline in July 2006. Husband Leonid Milkin was serving with the National Guard in Iraq at the time of the slayings.

Schierman later admitted to setting the Slater Avenue home on fire, but does not know how the people were killed. He could face the death penalty if convicted.

Deputy King County Prosecutor Scott O’Toole, who has contended that Schierman’s DNA is linked to the killings, made his remarks during closing arguments at the King County Superior Courthouse Thursday.

“This is the day this man sits down to his banquet of consequences,” O’Toole said. “That man stayed in the home but when he was done … that family was dead.”

O’Toole went over some of the key evidence again with the jury and said that Schierman’s actions were very much premeditated.

“In the last furious moments of their lives … they saw the person who took their lives,” O’Toole said. “That man is sitting in this courtroom and his name is Conner Schierman … Truth does matter and I’m going to ask you to find the truth and find this man guilty as charged.”

Defense attorney James Conroy ended months of silence when he made his closing argument to the jury Thursday.

“We would never minimize the tragedy of this case – ever,” Conroy said. “The decision you make could mean the difference between life and death.”

If Schierman is convicted on all four counts of aggravated murder, the trial will immediately move to a penalty phase where another jury will decide the option of life in prison with parole or the death penalty.

Conroy explained that alcoholism is a genetically inherited trait and that Schierman tried to take responsibility for his actions by seeking therapy. His family “always believed he was a good person,” and he was praised by his employers, particularly when he was a maintenance worker at Carillon Point in Kirkland.

Defense attorneys Conroy and Peter Connick tried to convince a jury that the 28 year-old Bellevue native suffered an alcoholic blackout and woke from it to find himself covered in blood and surrounded by the dead in a master bedroom of a home. Schierman has pleaded not guilty and made his claim during an initial interview with police when he was arrested in 2006.

Conroy argued instead that the lack of evidence tying Schierman to the crime scene, including a flashlight, was insufficient and suggested some unknown third party may have been involved in the slayings.

“Maybe someone else was there,” Conroy said. “Maybe someone was there before Conner.”

The attorneys made the unusual move that Schierman either did not commit the killings or was too drunk at the time to have premeditated them. While voluntary drunkenness isn’t an excuse for criminal conduct, the defense argued that he was not able to premeditate the act of murder.

Conroy said that when Schierman’s friends found out about the Milkin house fire and contacted him they found him on his bed, his face buried in a pillow. Conroy said it was because he was scared and “had no idea what to do.” O’Toole said he was trying to hide the numerous injuries to his body, including his face and neck that had deep scratches, and a puncture wound on his left arm sustained during his struggle with the victims.