An unexplained popping sound, or the stray mark of a tire on a car bumper.

The guilt or innocence of Aimee Michael in the deaths of five people in an Easter 2009 crash could come down to such evidence.

Or it could boil down to the simple fact that she fled the scene of the crash on Camp Creek Parkway and repaired the gold BMW she was driving.

The lawyers for and against her wrapped up their cases in a criminal trial early Wednesday afternoon that could send her to prison for decades. The jury — nine men and two women — began deliberations at about 4 p.m. They deliberated until 5:30 p.m. and will resume at 9:30 a.m. Thursday.

Michael, 24, has been on trial in Fulton County Superior Court since last week for her role in the deaths of an entire family in one car and of a little girl in another.

She is the daughter of a former Atlanta elementary school teacher and a Department of Defense employee who was in Saudi Arabia at the time of the crash. She had graduated the year before from the University of Pittsburgh with a major in psychology, and had planned to go on to business school — and even filed an application with Wake Forest University four days after the crash.

But the events during an ice cream run to Publix on April 12, 2009, changed her life. She admitted to police that she fled the scene and, with her mother’s help, paid a body shop to repair the damage. Before the trial began, Michael rejected a plea deal that would have sent her to prison for 50 years. Her mother, Sheila, pleaded guilty last week to tampering with evidence and hindering the apprehension of a criminal, and is to be sentenced after her daughter’s trial.

In an unusual move, Aimee Michael’s lawyer, W. Scott Smith, admitted guilt at the trial’s start, telling the jury that his client did flee the scene. On Wednesday, he urged the jury to find Michael guilty of six felony counts of hit and run and one misdemeanor count of tampering with evidence.

But Smith argued that Michael did not cause the chain-reaction collisions that killed three children and two adults. He said Michael was not guilty of five felony counts of vehicular homicide, a felony count of serious injury by vehicle and misdemeanor counts of failure to maintain a lane and reckless driving.

Smith urged jurors to pay close attention to the evidence from the scene, such as the tire marks on the road and on the bumper of a silver Mercedes that Michael collided with.

A former Georgia State Patrol crash investigator testified for the defense that Robert Carter, who was driving a silver Mercedes alongside Michael, caused the crash by driving into the BMW from behind, initiating a loss of control by both vehicles.

Smith argued that the tire mark on the Mercedes bumper that was shown to jurors came from that first impact and that the state failed to prove it didn’t. The state crime lab could have analyzed the rub on the bumper to determine which tire caused it, but didn’t, he said.

That was the reasonable doubt needed to acquit Michael, he said.

“This one piece of evidence is your doubt,” he said. “This is like finger print evidence. It’s DNA on the scene.”

But two experts for the prosecution – a Fulton County police officer and a civil engineer from North Carolina – testified that the BMW lost control on its own and slammed into the Mercedes.

A witness who was driving ahead of the mayhem testified that she heard a “popping” sound before she looked into her rear view mirror and saw what happened next.

The cars collided then spun across the highway into the westbound lanes. The Mercedes then smashed head-on with a Volkswagen Beetle.

Carter and his wife, Delisia, were killed instantly, according to the medical examiner who performed the autopsies. Their 2-month-old son, Ethan Carter, and Delisia Carter’s daughter Kayla Lemons, 9, were killed almost instantly when they inhaled hot air after the car ignited.

In the Volkswagen, Morgan Johnson, 6, was killed. Her mother, Tracie, 43, survived but suffered broken legs, a broken hip and collarbone and damage to her spleen and liver.

A westbound Honda Accord also was caught in the crashes, but the woman driving it was not injured and neither were her two children.

Smith argued that the popping sound was the Mercedes bumping into Michael’s car before she lost control and swung back into the Mercedes. There was no clear evidence to support – or contradict – that contention, so it’s up to jurors to decide whether it happened.

What does seem clear is that the BMW came to rest, and Michael then drove away to have her car repaired. This is what she told police on April 23, soon after they hunted her down. Her story was confirmed by the man who fixed her car and by cell phone records indicating that they spoke.

Prosecutors said the evidence at the scene supported their contention that Michael caused the crash. But Assistant District Attorney Tanya Miller urged jurors not to “go down the rabbit hole” of competing expert witnesses.

Miller contended that Michael’s flight itself, and her destruction of hard evidence, was circumstantial evidence that she caused the crash.

“She fled. She ran. She left those people burning,” Miller said. “What innocent person would do that?”