How a beloved Georgia father was gunned down as he dropped off his son at preschool

When Rusty Sneiderman dropped off his son at a preschool in the Atlanta suburb of Dunwoody, Georgia, on Nov. 18, 2010, the morning calm was shattered by the sounds of gunfire.

Sneiderman, 36, lay dead after someone drove up in a silver minivan and fired four shots at close range before fleeing, according to witnesses.

"It was so surreal, the experience, in that there was no chaos or running or yelling or anything. He just walked back to his van. It didn't look like what I would think a murder would be," witness Chris Lang told "20/20." "And everyone thinks they would know what you'd do. You don't."

A new "20/20" episode, "Fatal Disguise," airing Friday, Nov. 15, at 9 p.m. ET and streaming the next day on Hulu, examines the case.

Witness Larry Minogue, who dropped off his own son at the preschool an hour before the shooting, said he encountered the suspect.

"I noticed his black beard. And I could tell, as far as how dark it was, that it didn't belong," he told "20/20." "I knew it was a fake beard."

Hearing about the shooting on the radio later, he connected the person he saw to the incident and contacted the Dunwoody police. Based on his description, they released a sketch of the suspect.

Looking for any leads, detectives also spoke to Sneiderman's wife Andrea, and asked if anyone had shown a romantic interest in her. She noted that her boss had recently made a pass at her during a business trip, but she turned him down.

"Andrea is totally baffled. She doesn't know who would kill her husband, why her husband would be killed," J. Tom Morgan, who was Andrea's attorney at the time, told "20/20." "She's very distraught."

Rusty had made two 911 calls in the period leading up to the shooting. The first came a month before his death when he and Andrea were at home, with Rusty calling to express concern that someone was trying to break into the family's home.

The second call, which happened a week ahead of the murder, was even more concerning. Rusty told police he spotted someone hiding outside his house. The person ran away, he said, but he thought they may have had a gun in their back pocket. Police responded to both calls and investigated but no arrests are made.

After extensively reviewing surveillance camera footage of the shooting scene, detectives figured out that the suspect was driving a 2011 Kia Sedona minivan. This model had only recently become available, and the stickers on the windshield suggested it was a rental.

Their investigation led them to a lot in north Georgia, where a search of the minivan turned up synthetic hairs -- just like those from a costume beard.

Detectives also connected the rental to Hemy Neuman, a General Electric executive and Andrea's boss. He spoke to police voluntarily, admitting his feelings for Andrea and acknowledging that he rented a Sedona on Nov. 17. However, he denied driving it to the preschool and murdering Rusty the following day.

Neuman was later arrested and pleaded not guilty to a charge of malice murder.

However, when his trial began, Neuman admitted to shooting Rusty. He also acknowledged during mental health evaluations with a court-appointed psychiatrist that he had been lurking outside the Sneiderman home on the day of Rusty's second 911 call, according to his defense attorneys.

Neuman said he wasn't guilty because he was mentally ill at the time, and his defense team painted a picture of what they said was a troubled man with undiagnosed bipolar disorder who, according to them, had a traumatic childhood.

"His father was a concentration camp survivor. Very difficult man, very distant man, not very loving," Bob Rubin, Neuman's defense attorney, told "20/20." "Our belief was, because of his bipolar disorder, he didn't have the capacity to know right from wrong at the time of the shooting of Rusty Sneiderman."

Neuman also claimed to have been visited by a demon with a deep voice, who he said sounded like singer Barry White, and an angel that he claimed sounded similar to "Grease" actor and singer Olivia Newton-John in summer 2010, and that the voices told him Rusty needed to die. When the psychiatrist asked if he still thought the demon was real, Neuman acknowledged that it probably wasn't.

By contrast, the prosecution painted Neuman as a liar who was faking his mental illness and wanted Rusty out of the picture so that he could marry Andrea. Rusty also had a life insurance policy worth $2 million, and prosecutors alleged that Neuman wanted that money as well.

In the mental health evaluations, Neuman alleged that he and Andrea had shared a kiss and, during a business trip, had watched a movie alone together in a hotel room. Andrea denied that either of these events happened. Neuman also said in the mental health evaluations that he and Andrea never had a sexual relationship.

Andrea took the witness stand for the prosecution at Neuman's trial, and the nature of her relationship with her boss took center stage.

Both the defense and the prosecution tried to link Andrea to the shooting, even though she wasn't the one on trial.

"Our theories were very, very close. They were saying she led him all the way up to it, but didn't necessarily plan it," Robert James, DeKalb County district attorney at the time, told "20/20." "And we were saying, yeah, she was the motive for it, but we believe she perhaps had something to do with it as well."

Andrea called Neuman multiple times on her way to the hospital, James told "20/20." She said she was only contacting him to say she had left the office because something happened to Rusty.

Andrea denied having an affair with Neuman and any involvement in Rusty’s shooting or the plan to kill him.

In March 2012, a jury found Neuman guilty but mentally ill and the judge sentenced him to life without parole.

Responding via a statement after the sentencing, Andrea said she was "grateful for and relieved by" the verdict and described her late husband as an "amazing man."

However, Rusty's family, led by his brother Steve, were suspicious of Andrea.

"It's clear to me that Andrea is covered in Rusty's blood," he said at a press conference at the end of Neuman's trial. "We'll have no peace until everyone involved in Rusty's death is held accountable for their actions."

Five months later, Andrea was arrested and charged with murder, obstruction, false statements and perjury. She pleaded not guilty to all charges.

James argued that the charges were based on very strong circumstantial evidence, including her calls to Neuman on the way to the hospital and a computer search for death benefits the night before the shooting.

"All you have is that she may have lied about having an affair," J. Tom Morgan, Andrea's attorney, told "20/20. "That doesn't mean she had anything to do with her husband being murdered."

Nearly a year after Andrea's arrest and just as the trial was about to begin, DA Robert James shocked court observers by asking the judge to dismiss the murder charges against Andrea due to insufficient evidence.

"If you say that the prosecutor is a minister of justice, then you have to own that," James told "20/20." "It's not what you know, quite frankly. It's what you can prove."

He noted that the computer search for death benefits "very likely could've been a recurring search" and may not have been related to the murder. James acknowledged that Rusty may have been the one looking for that information.

Andrea was no longer charged with murder, but prosecutors moved forward with a trial in August 2013 on the other charges, including lying on the stand and hindering the investigation into her husband's murder.

"I was hoping Hemy would point a finger at Andrea to lessen his sentence. He never, never considered that option," Bob Rubin, Neuman's attorney, told "20/20." "Hemy continued to express his love for her."

Andrea was convicted of 9 out of 13 counts against her and sentenced to five years in prison. After 10 months, she was released on parole with credit for time served both in jail and under house arrest during her trial.

In 2015, Neuman's conviction was thrown out after Georgia's Supreme Court determined that the trial court had violated attorney-client privilege by allowing into evidence some of his mental health evaluations. At a new trial, his defense team maintained the same argument that delusions drove him to kill Rusty.

A jury again found Neuman guilty, but this time not mentally ill, and he was sentenced to life in prison without parole.

"Hemy will never get out of prison," Rubin told "20/20. "He's going to live his life regretting his actions, regretting that he has no relationship with his own children, regretting that he lost everything."

Andrea no longer has a criminal record and has been exonerated of guilt due to the First Offender Act, a Georgia law that focuses on nonviolent crimes.

"Once you have served out your sentence, probation included, then you know, your sins, your crimes are erased from the record," James told "20/20." "And she wasn't given special treatment. She just wasn't treated any worse than anyone else."

Meanwhile, Rusty Sneiderman's family continues to mourn his loss.

"He had so much more to offer the world," his brother Steve said during a 2012 interview with "20/20." "The world is so much poorer because he's not here."