UPDATE Nov. 30, 2017: A star student at an Ivy League school made headlines when he went on trial for the murder of his father.

Now Charlie Tan is back in the news after being arrested again and faces new charges.

March 24, 2017

The body of wealthy businessman Jim Tan was found lying on the floor of his study, disfigured almost beyond recognition with a shotgun blast to the face, inside a New York home in a neighborhood of Pittsford, a suburb of Rochester, in February 2015.

Jim Tan's Ivy League son Charlie Tan stunningly confesses at the scene of the gruesome crime, saying that Jim Tan was going to kill his wife, Charlie's mother.

But conflicting evidence fuels suspicions that Charlie may have actually been trying to save his mother Jean from something else -- a murder rap.

Chinese immigrants Jim Tan, 49, wife Jean and youngest son Charlie, 20, were living the American Dream in a beautiful home in Pittsford, N.Y., an affluent community in the Rochester area.

"He [Jim Tan] was the owner of Dynamax Imaging. It's a digital optics company. They make digital sensors for cameras, phones, that kind of thing," said Jon Hand, a Democrat & Chronicle reporter who covers the story. "It was a business that did well."

Hand says success was running in the family, with son Charlie already far exceeding his parents' high hopes for him.

"Charlie was a superstar kid," said Hand. "President of his student class at a very good high school, Pittsford Mendon, which is one of the top schools in the state."

"Well-liked in school, did well in school, did well athletically," said retired Montgomery County Sheriff's Detective Steven Peglow.

So well that Charlie had gone on to become an Ivy Leaguer at prestigious Cornell University in Ithaca, where the sophomore was continuing his academic success and further showing off his athletic prowess on the football team. He was also popular.

But behind Charlie's affable demeanor and broad smile, there lay some painful family secrets. And that was about to be exposed with the squeeze of a trigger.

James Nobles, Charlie Tan's defense attorney, says Jim and Jean Tan had reportedly been having violent arguments.

"There was definitely a longstanding history of domestic violence in the house," said Nobles.

Jean is said to have frequently shown signs of being physically abused.

"One day she's fine and she's well, and the next day she has an injury. Her knee is bandaged or she's got a bandage on her head or something like that. 'I bumped my head,' you know, the classic cliche excuses of a battered woman," said Tan's defense attorney Brian DeCarolis.

The police had been called to the Tan home more than a dozen times over the years. And just weeks before Jim Tan was found murdered, an apparently terrified Jean had called 911 again.

"She was being assaulted or abused by her husband," said Monroe County, N.Y. District Attorney Sandra Doorley.

No charges were filed, but officers left Jean with a business card with contact info directing her to help for domestic violence.

"My understanding is that she had started an order of protection against her husband, and that she never followed through," said reporter Jon Hand.

And her son's defense attorneys say Jean also saw a divorce lawyer shortly after.

Then, just a week later, something happens that sends Charlie scurrying back to his parents' home from his dorm at Cornell. Nobody knows for sure what the emergency was.

"We've speculated and assumed that there was some communication between Charlie and his mother which caused him at that point to pack up his belongings and come home and assist her in some way," said Doorley.

"We know there had been some communication between the two of them [Charlie and Jean] about something that happened at home which was prompting his trip to go there," said defense attorney James Nobles.

Four days later, on a Monday night in February 2015, police received a hysterical 911 call from Charlie's mother Jean. Cops arrive at the Tan home to find Jean waiting outside with Charlie, who surprises them by confessing to killing his father.

"They asked where his dad was. He said 'He's dead. He's upstairs. I had to do it. He was going to hurt my mom,'" said retired detective Steven Peglow, who worked the case.

Jean corroborates her son's story.

"Jean Tan says 'My son did it.' Charlie agrees that he did it. He directs the sheriffs to the location where the weapon is found," said D.A. Doorley. "But then you look at the crime scene, it appeared that Jim Tan was sitting at his desk, working, answering emails. There didn't appear to be a struggle. It looked like he was taken by surprise. There was not an item on his desk that was out of place."

Then there's the horrific way Jim Tan was killed. His body was found lying under his desk in the study with three wounds inflicted by a 12-gauge shotgun.

"Once in the chest, one sort of in the arm, and then a facial shot that pretty much removed his whole face," said reporter Jon Hand.

"The shotgun was placed next to his face. His face was obliterated while he was still alive," said Monroe County Assistant District Attorney William Gargan.

Charlie was arrested and charged with second-degree murder on the strength of his crime scene confession.

"He was very calm. Very, almost business-like," said D.A. Doorley.

But from the moment lead detective Steven Peglow arrived at the Tan home, he had suspicions Charlie and his mother were both lying about when Jim Tan was actually killed.

"There was an odor of what bodies smell like when they have been around for a while, when they have started to decay, and you get that smell when you walked into the home," said Peglow.

"There was dried blood all over," said Doorley.

"I realized that Jim Tan had come out of rigor mortis," said Peglow. "When someone dies, their body stiffens and it stiffens for 12 to 24 hours. And then the body goes out of rigor mortis and becomes very limber again."

The coroner would conclude Jim Tan had been dead for 48 to 72 hours.

"He certainly didn't die on Monday. He certainly didn't die on Sunday. You start getting into Saturday," said James Nobles.

"Jim had a computer in front of him and one of the investigators turns it on, and there was emails on the computer that had not been read since the previous Thursday," said retired detective Peglow.

That's the same day his son Charlie had mysteriously rushed back to the family home from Cornell.

"We felt confident that Thursday evening was the last time he [Jim Tan] took a breath," said Gargan.

That sparks accusations that Jim's wife Jean must have staged the 911 call she made four days later.

"No question in my mind that that call on Monday night was completely fake," said Nobles. "She also says 'I saw something happen.' We know she didn't see something happen on Monday night. It's impossible. It's what the coroner said."

Investigators have no evidence to indicate it was Jean who actually committed the murder, but they gathered a lot of circumstantial evidence pointing to Charlie as his father's killer, learning that he had gotten hold of the murder weapon that same Thursday that he returned home from Cornell.

They uncovered surveillance video of Charlie trying to buy the shotgun at a Walmart near the university on his way back to Rochester, only to be turned away because he reportedly didn't have the necessary documents. But the surveillance video then shows a friend going back to the store and buying the gun for Charlie. Our affiliate WHAM-TV reported that shotgun became a centerpiece of the murder case against Charlie Tan.

"We believe he loaded it because his fingerprints are on the ammunition, came home and essentially ambushed his father as he sat at his desk," said Doorley.

Investigators found a foreboding email Charlie sent to his fraternity brothers at Cornell that same day. He titled it "Showtime," and it reads: "In the coming days you'll start to hear things in the news and possibly get a couple of visits from authorities. Don't listen to anything you hear. A few already know my true story, and in due time you will also."

"It shows his intent," said Doorley. "It shows this was purposeful for him, and he knew what he was going to do."

But Charlie's defense attorneys interpret the email as an indication Charlie knew his mother had perhaps already killed his father.

"I explain it as a cover-up for his mother," said James Nobles. "He says 'You're going to see what happened,' and he also, importantly, says 'What you're going to hear isn't true.' That suggests to me that he's taking the fall for his mother."

It was the most sensational and dramatic trial Rochester, New York had seen. The courtroom was packed, and just about everyone except the prosecution seems to be rooting for popular 20-year-old Ivy Leaguer Charlie Tan, who stands accused of the bloody shooting murder of his wealthy businessman father Jim Tan.

"It's usually the victim has all the support from family and friends," said Doorley. "We had nobody on our side. Everyone was supporting Charlie."

But police and prosecutors are confident they have all the evidence they need to get a conviction: They have the murder weapon; surveillance video of one of Charlie's friends buying the gun for him just hours before the fatal shooting; a foreboding email Charlie had sent his fraternity brothers at Cornell University warning them they would soon hear some shocking news they shouldn't believe; and a brief, informal confession Charlie gave to cops at the crime scene.

The prosecution even has Charlie's alleged motive: "To protect his mother," said Doorley.

Jean Tan, who was allegedly being abused by her husband and living in fear for her life.

"There was definitely a longstanding history of domestic violence in the house," said Charlie Tan's defense attorney James Noble.

But Charlie's defense team is betting all of that still won't be enough for the prosecution to win the case.

"Basically our entire defense was built around 'You don't know who shot this person,'" said Nobles. "Nobody knows what's going on in this house."

And Charlie's attorneys hammer away at the evidence the prosecution doesn't have.

"They had no eyewitnesses to put Charlie at the scene," said Nobles.

Plus, the only forensic evidence was Charlie's fingerprints on the ammunition in the shotgun.

"He could have touched them before the fact, after the fact," said Nobles. "I mean, he has no fingerprints on the gun, so there's no evidence to suggest he's loading the gun."

And the weapon didn't have a trace of Charlie's DNA on it.

"You've got three separate DNAs on this, none of which belong to him," said Nobles.

Then there's the prosecution's strongest piece of evidence: The brief statement Charlie made to cops at the crime scene that the prosecution is taking as a confession.

"We had the defendant Charlie Tan saying 'I had to do it. I did it. He was going to kill my mother,'" said D.A. Doorley.

The defense scoffs at that.

"It's not a confession. It's equivocal at best," said Nobles. "It could be that he's covering. 'I had to do it' -- it's not clear what he had to do."

"It's not the same as him saying 'I killed my father,'" said Crime Watch Daily Legal Correspondent Amy Dash. "So that's how specific you have to get when you want to present evidence that somebody tries to prove that somebody confessed."

And it was never clarified.

"No one asked a follow-up question," said Nobles.

Charlie had immediately retained an attorney and never said another word to investigators after that.

"There was no interrogation with him at the police department," said Nobles.

The defense casts suspicion upon Charlie's mother Jean, who had also lawyered up and had never spoken to police.

"His mother frankly has a much greater motive, a much greater incentive, a much greater hatred in which to fuel this type of a violent act," said Nobles.

And they suggest Jean's 911 call to police was faked, made on a Monday, four days after, they say, her husband was murdered.

"We know she didn't see something happen on Monday night. It's impossible," said Nobles.

The defense tells the jury Charlie Tan could have been taking the murder rap for his mom.

"I'm asking you to take a look at Jean Tan, not because I'm telling you or suggesting to you that she killed Jim Tan, but you have to agree with me that there's far more evidence to suggest she did it than Charlie did it," said Nobles. "If you agree with that statement you have to find him not guilty beyond a reasonable doubt."

The jury deliberated for five days without being able to reach a unanimous verdict, and Judge James Piampiano declared a mistrial.

"And we would start this case over again," said Doorley.

But when the prosecution and defense return to court expecting to discuss the date for a new trial, Judge Piampiano makes a jaw-dropping announcement: He dismisses the case. The judge declared to everybody's surprise that there is not enough evidence against Charlie to justify a new trial.

"It was unfathomable because nobody saw that coming," said retired detective Peglow.

Charlie Tan and his defense team are ecstatic, while the prosecution is left in stunned disbelief.

"It was a shock. It wasn't what we were expecting," said Doorley.

Even the defense concedes such a ruling by a judge has little precedent.

"It is rare," said Nobles.

District Attorney Sandra Doorley cries foul.

"There was clearly, in my opinion, under the law, legally sufficient evidence to allow that case to go to a jury for a decision," said Doorley.

"This is an egregious error," said assistant D.A. Gargan.

"People feel that the judge essentially took the decision away from the jury," said Amy Dash. "But what people don't realize is that this is something that law allows the judge to do."

But when furious lead prosecutor Bill Gargan objects, Judge Piampiano threatens to have him arrested and handcuffed right there in court.

"This is the only time in my career I've ever been threatened with jail by a judge," said Gargan. "But had he sought to put me in jail I would have gladly gone to ensure that our voices were heard in relation to that absurd decision."

A smiling Charlie Tan walks out of court an exonerated free man.

"I think he was surprised by everything that happened," said Nobles.

The story does not end there with all charges against Charlie Tan being dropped. Currently prosecutors are appealing the judge's decision.

"We argued in front of our appellate division last week," said D.A. Sandra Doorley.

But Doorley admits the chances of getting a new trial are beyond slim.

"It is an uphill battle," said Doorley.

And if the prosecution loses, as expected, the case will indeed be over.

"Judge Piampiano was right in what he did, that they can't appeal it, that there's nothing they can do," said Nobles.

"He felt their case was so weak that it didn't even support bringing the murder charge," said Amy Dash. "And the reason is they had a lot of these circumstantial pieces of evidence, but with each one you had to make a logical leap in order to connect him to the crime."

So the murder of Jim Tan remains as much of a "whodunit" now as it was in the beginning.