Thomas Gilbert Jr killed his father at his Beekman Place apartment in Manhattan on January 4, 2015. Photo / Getty Images
It started with a cut to his allowance, prosecutors said.
According to Manhattan District Attorney's Office, Princeton graduate Thomas Gilbert Jr. pulled a gun on his millionaire hedge-fund father after his already tightened weekly money was decreased to $300.
On Friday, Gilbert was sentenced to 30 years to life in prison for the murder of his dad as his mum begged the judge for mercy, according to New York Post.
"We were once a very happy family and want to be happy again," the Ivy League graduate's mother Shelley Gilbert put an unusual twist on her victim's impact statement in Manhattan Supreme Court by pleading for her son's leniency.
"We need Tommy to be given as light a sentence as possible," she told Judge Melissa Jackson, according to the New York Post. "I ask that you give him a chance and give him hope for his future, not just for him, but for us as well.
"I know if my husband was speaking from heaven, he would be saying the same thing as well."
A jury convicted the Princeton graduate on one count of murder in the second degree and two counts of criminal possession of a weapon, the district attorneys said.
On January 4th 2015, the Ivy League graduate sent his mother Shelley out to fetch him a Coca Cola and a sandwhich before he opened fire on his father.
Earlier in the day, his parents had dropped his allowance from $400 to $300 a month.
"The last thing Thomas Gilbert Sr. ever saw was his own son pressing a .40-caliber semiautomatic pistol into his head and pulling the trigger," Assistant District lawyer Craig Ortner had told jurors.
Gilbert Jr. left his father's slain body on the floor for his mother to find on her return to the apartment minutes later.
Craig Ortner told the court: "This was a cold, calculated, premeditated murder committed by a 30-year-old man."
Despite Gilbert's internet search history proving he researched murder online, his mum insists that her son was "struck by schizophrenia" and that she "wishes" the judge "and everybody in court" could have known Gilbert before that.
"I know you are not responsible for assigning Tommy to his next location, but I ask you to strongly recommend he be committed to a [psychiatric] hospital close to home so we can visit him regularly," said Shelley.
"Visits are therapeutic for him and essential for keeping what is left of our family together."
Shelley went on to say that "my husband would still be alive today" if her family was able to get her son into a psychiatric hospital 15 years ago.
"The state of New York and its lack of adequate treatment for the very mentally ill has caused the agony we have had to endure for a very long time," she said. "If my schizophrenic son ends up in a prison in upstate New York where we are not able to visit him often that would add to the trauma my daughter and I have to endure."
Before Shelley gave her statement, prosecutors noted to the judge that the law said victims who are family of the killers are supposed to speak only in support of the victim. But defence lawyer Arnold Levine argued she "knows what the victim's views would be" and Jackson agreed to let her talk.
Jackson later addressed Gilbert before she handed down the sentence, saying, "You were not insane at the time you committed the crime and killed your father."
The judge, who told Gilbert, "there's no doubt that you have mental issues," added, "you were not insane, and you're not insane now."
Ortner had argued that Gilbert may have suffered from mental illness but he knew exactly what he was doing when he pulled the trigger.
Ortner had said that Gilbert, driven by greed and rage, "threw the ultimate tantrum."