But the signs of a volatile, bullying personality became steadily more pronounced over time, especially after an ATV accident last year. Many who knew Mr. DiNardo said that his mood became especially dark.
On Thursday, he confessed to the Bucks County prosecutor that he and a cousin, Sean M. Kratz, also 20, were responsible for the brutal killings this month of four young men who sought Mr. DiNardo out as their marijuana connection. Mr. DiNardo and Mr. Kratz have yet to make a court appearance and have not entered pleas.
Prosecutors said that Mr. DiNardo lured the victims to a remote family farm in northern Bucks County over two days, and along with Mr. Kratz shot them, ran one of them over with a backhoe and burned three of the bodies.
Chris Hellmuth, who people in Mr. DiNardo’s orbit said was close to him, wrote in a Facebook post on Saturday that the two were best friends since fourth grade, but grew apart because of Mr. DiNardo’s behavior after an ATV accident. Mr. DiNardo was briefly hospitalized for a mental health issue.
“The Cosmo I knew for over 10 years would never be capable of anything like this,” Mr. Hellmuth wrote.
During Mr. DiNardo’s confession, the prosecutor’s office said, he also claimed that, at 15, he killed two people in Philadelphia.
Mr. DiNardo grew up in the middle-class suburb of Bensalem, the oldest child of Antonio and Sandra DiNardo. Antonio DiNardo owns a concrete company, Metro Ready Mix and Supply, and inherited a lucrative real estate portfolio after the death of his father, for whom Cosmo DiNardo was named. Sandra DiNardo runs a trucking company, Bella Trucking, and she and her husband built a profitable partnership by selling concrete and delivering it.
A neighbor of the DiNardos in Bensalem said Mr. DiNardo’s grandfather and father, who goes by Tony, built all of the stucco homes on their cul-de-sac. “He’s a workaholic, Tony,” said the neighbor, a physician, who asked to be identified by only his first name, Abid.
Sabrina Gramiak, 23, who said she attended St. Charles Borromeo School, a private elementary school in Bensalem, at the same time as Cosmo DiNardo, remembers him as “a normal boy who just got into minor trouble.” She said he was once given the “Peacemaker of the Month” award. By eighth grade, he was bench-pressing 220 pounds and orchestrating well-attended pool parties at his home.
But if there was a social side, there was also a scary, dark one, acquaintances said. While he was a teenager, his anger and aggression could not be talked down. At 15, he punched two strangers at a mall when he saw them talking to his girlfriend, according to a friend.
“Cosmo was crazy,” said Amber Peters, 20, whose boyfriend was once close to Mr. DiNardo. “He’s been talking about killing people since he was 14.”
She said Mr. DiNardo made unwanted and obnoxious overtures to young women on social media. “He randomly messages girls, saying, ‘Hey, babe,’ calling them hos and trying to have sex with them.”
After high school, most of his friends went into the work force and started families. Mr. DiNardo enrolled in August 2015 as a commuter student at Arcadia University in Glenside, Pa., about 20 miles west of Bensalem, and declared an interest in biology.
At a concert before the semester began, he invited a group of female students to his house to swim. They declined, but Mr. DiNardo did not leave it at that.
“He texted me every day after that asking me to hang out,” said Sara Dinner, a student from Mechanicsburg, Pa. “I eventually blocked his number because if he didn’t get his way, he would get so upset. I think he had anger management issues, honestly.”
Mr. DiNardo completed only one semester at Arcadia, but the next fall he began hanging around campus. The campus police received complaints of “verbal incidents” by Mr. DiNardo that “unnerved university community members,” said Laura Baldwin, a university spokeswoman. The school sent him a certified letter stating that if he returned to campus, he would be treated as a trespasser. The school also notified the local police, Ms. Baldwin said.
Last week, a woman posted a series of messages exchanged on Facebook in December and January that show Mr. DiNardo aggressively pestering her for a date and more. “Leave me alone please,” the woman replied, to which he answered, “why baeb I’m pretty cute and so are you,” and, “i wanna make babies asap.”
The woman confirmed that the exchange was authentic, but like several acquaintances of Mr. DiNardo’s who spoke of his behavior, asked not to be identified by name.
After he left Arcadia, Mr. DiNardo worked for his father’s concrete company, but he wrote on Facebook in November that he had moved on to sell “firewood,” which some friends said was a code for drugs. Friends said he sold guns and marijuana, and one friend said he wanted to move up to selling harder drugs and larger quantities.
Friends and acquaintances said Mr. DiNardo changed last year after he crashed a four-wheeler while alone in the woods on the family farm in Solebury Township, about 45 miles north of Philadelphia. According to some accounts, he was stranded for hours, suffering from broken bones, until his father and younger brother found him. Some friends said he suffered a serious head injury.
A longtime friend said: “That incident drove him over the edge. He was a more violent individual.” The friend asked not to be named because of a desire to not offend Mr. DiNardo’s family and an agreement among his friends to stay silent.
At an arraignment hearing last week, a Bucks County prosecutor said Mr. DiNardo was once diagnosed with schizophrenia. Members of his family and a lawyer representing Mr. DiNardo declined requests for more information about his mental health. One longtime friend said Mr. DiNardo twice spent time in a mental institution.
Mr. DiNardo, according to the authorities, instigated the killings of four men — Jimi Taro Patrick, 19; Dean Finocchiaro, 19; Thomas Meo, 21; and Mark Sturgis, 22 — with Mr. Kratz as an accomplice to three of them. They were each charged with multiple counts of homicide.
Mr. Kratz, who has a history of burglary, theft and other arrests, grew up moving around different Philadelphia neighborhoods and suburbs. He worked from 2014 to 2016 as a dishwasher at a retirement community, The Philadelphia Inquirer reported, but was better known by some people for terrorizing his former girlfriend’s neighborhood.
Residents recalled him as the skinny teenager in a black hoodie accused of breaking into homes and stealing jewelry and landscaping tools, the newspaper reported. His former girlfriend’s mother said she had long suspected he stole her Yorkie.
Over the past six months, Mr. DiNardo’s volatility had become increasingly public. In February, a neighbor in Bensalem, where Mr. DiNardo still lived with his parents and three younger siblings, called the police after Mr. DiNardo was seen walking down the street, shooting a 20-gauge shotgun in the air. He admitted to an officer that he was not legally allowed to possess firearms because of his prior mental commitment, police records show.
On Snapchat, Mr. DiNardo ranted about seeking revenge, appearing bloody in one video after he said he got into a fight at a strip club. In a selfie, the one in which he appeared bare-chested and wild-eyed, he aimed a revolver mounted with a laser at the phone.
Over the Independence Day holiday, a few days before the four men went missing, he sent an ominous video warning in a private Snapchat message to a few dozen friends, according to a person who watched it. He threatened to kill people who owed him money and to get away with it, speaking while lying down with guns arrayed behind him.
Now friends are trying to make sense of how catastrophically his life went off the rails.
On Sunday evening, around 500 people, including some of the victims’ family members, attended a candlelight vigil on the grounds of a memorial for the Sept. 11, 2001, attacks near Newtown, Pa. “It’s really about the community coming together and healing,” said Gloria Cugine, one of the organizers, before the 35-minute ceremony.
Mr. Hellmuth, a student at Drexel University, according to his Facebook page, wrote that he was not trying to excuse Mr. DiNardo’s behavior as he tried to process his own shock and pain about it.
“His parents never in a million years thought their son would ever be involved in something like this nor did they raise him in any way that made him do something like this,” he wrote.
Source: New York Times