Former GE engineer Hemy Neuman showed no emotion Thursday afternoon after a DeKalb County jury found him guilty but mentally ill in the November 2010 fatal shooting of Rusty Sneiderman outside a Dunwoody daycare facility.

He was stoic as DeKalb Superior Court Judge Gregory Adams imposed the harshest sentence possible: life in prison without the possibility of parole.

For prosecutors, it was a fitting response. They had argued that Neuman was a cold-blooded, calculating killer who robbed two young children of a father, two parents of a son and a brother of a younger sibling and best friend.

"He had no right to take Rusty from us," said Steve Sneiderman, Rusty's brother, in a victim impact statement delivered prior to sentencing. "Our lives have been shattered. There’s nothing this court can do to ever make us whole again."

DeKalb District Attorney Robert James said he could not yet discuss whether his office will file criminal charges against the victim's widow, Andrea. James had implied during his closing argument that the woman was Neuman's co-conspirator.

"It is something we have under review right now," James said. "Stay tuned."

Defense attorney Doug Peters was much less circumspect, saying Andrea Sneiderman should be charged with first-degree murder. The defense team had acknowledged the shooting but said the 49-old-year-old Neuman was mentally ill at the time.

"I believe Andrea Sneiderman planted the seed, primed the pump, stoked the fire," Peters told reporters Thursday. "I think the evidence in this case indicates quite clearly she knew how she wanted her husband murdered, and she manipulated Hemy Neuman to have it done."

Neither Andrea Sneiderman nor her immediate family were present for Thursday's verdict. In a statement, the widow's newly hired attorney, Jennifer Little, said her client "is grateful for and relieved by the jury’s guilty verdict and the sentence.

"Nothing can bring back her husband, but it is reassuring to her that, after all of the noise and distractions surrounding this case, some measure of justice has been done for Rusty," Little said.

Andrea Sneiderman, who has never publicly discussed her husband's shooting, plans to maintain that silence, according to the statement. "This trial has been extremely difficult for Andrea and her family," Little said. "They need time to grieve, and time to heal."

Meanwhile, Neuman's attorneys said they plan to appeal Thursday's verdict. The appeal must be filed within 30 days.

"We do respectfully disagree with the verdict. We feel that it extends the tragedy that was started back in 2010 when Hemy met Andrea Sneiderman," Peters said.

Before his sentence was imposed, Neuman apologized to Rusty's family.

"[Rusty] was a good man with so much ahead of him, and I'm so, so so sorry for their loss," Neuman said, his voice quavering. "They should've not had to undergo the sorrow, the pain and the loss."

Minutes later, the father of three was led away in handcuffs.

Neuman will remain at the DeKalb Jail awaiting transfer to the Georgia Diagnostic and Classification Prison in Jackson, said defense attorney Bob Rubin.

Until then, any decision on whether Neuman will be placed under suicide watch would be made by William Brickhouse, the jail's mental health director who testified last week that he neither thought Neuman was bipolar nor took a previous suicide threat seriously.

--Staff writer Mike Morris contributed to this article.