Authorities offered few details and, except for some witness accounts of fighting in the parking lot, the circumstances of the death were unclear Tuesday.
The incident, which happened shortly before 11:30 p.m., remains under investigation, Willingboro police said in a statement, and no charges were immediately filed. Willingboro police could not be reached Tuesday to confirm any of the accounts.
A couple of doors from the pizzeria at East Ridge Plaza on Beverly Rancocas Road is MVP Martial Arts, owned by Joseph Poole. He said Benson was one of about 40 guests at a birthday party for an 18-year-old Burlington County Institute of Technology student at his studio.
After the party, there was an argument in the parking lot, he said.
Over the weekend, tributes to Benson popped up on social media.
On Twitter, people tweeted condolences, some using the hashtag RIPDejour, and posted pictures, including one of him in a football uniform. On Tuesday, someone tweeted, "continuing to pray for all the family and young people affected by the loss of this young life."
On Facebook, a De'Jour K. Benson Memorial Fund page was created.
Benson's father, Kevin, is one of the high school's security officers, the district said.
At the family home, a family member declined to comment on Tuesday.
In the East Ridge Plaza parking lot, there was a memorial with stuffed animals on the concrete, including a white teddy bear with a graduation cap.
Antonio Parnell, a 16-year-old Willingboro freshman, left his size 12 blue-and-white Nike mud-stained football cleats at the memorial for Benson, a linebacker.
Parnell said Benson was "a kid that just wanted to see everybody around him happy."
On Friday, he said, "I shook his hand and said, 'I'll see you over the weekend,' "
Poole, 44, who is also a pastor, said his daughter, also a BCIT student, knew both Benson, a former student there, and the teenager celebrating her birthday.
Poole said he was at the studio at the start of the party, and an associate went in and out during it. Three adults were also there, but Poole said he did not know them.
"There was no alcohol there," Poole said, adding that "from what I understand," some guests were turned away because they smelled of alcohol.
He said the party was scheduled to end at midnight, but ended early because the guest of honor grew concerned about the large number present.
A viewing and services for Benson are set for Thursday.
Contact Darran Simon at 856-779-3829 or at email@example.com, or follow on Twitter @darransimon.
Inquirer staff writer Claudia Vargas contributed to this article.