PATERSON -- The teenager charged in an attack caught on video has received death threats since turning himself in to police, his attorney said.

Harley Breite asked Wednesday that his client, Kristian Gonzalez, be sequestered 23 hours a day at the Essex County Juvenile Detention Center in Newark for his own safety.

Gonzalez, 18, is the alleged attacker in a video showing a teen punching an elderly man in the face on Dec. 7, police said. He pleaded not guilty Wednesday before Passaic County Family Court Judge Daniel J. Yablonsky to charges of aggravated assault and endangering an injured victim.

Jerry Speziale, director of the Paterson Police Department, said he received numerous texts and phone calls about the video. Though it was quickly taken down, enough people reproduced it that police were able to identify the people shown. Police had been investigating the Dec. 7 assault before the video came to light, he said.

Gonzalez's arrest, and that of the 16-year-old who allegedly recorded the video, should serve as a warning, Speziale said.

"Don't you dare do this in our city," he said. "We will not tolerate it."

The 16-year-old pleaded not guilty to the same charges Monday.

Gonzalez is a Paterson resident attending Great Falls Academy. He turned 18 in late December, after the alleged attack. The Passaic County Prosecutor's Office has not indicated whether he'll be tried as an adult.

Breite asked that Gonzalez undergo regular medical and psychological examinations. The Paterson teen has been diagnosed with schizophrenia, oppositional defiant disorder and attention deficit hyperactivity disorder, Breite said.

Yablonsky denied Breite's request that Gonzalez be released with an electronic monitoring bracelet. Juvenile defendants aren't assigned bail. Yablonsky will periodically review Gonzalez's detention.

"It would be grossly unfair to waive him up [as an adult] just because there is media attention to this case," Breite said.

Breite said both he and Gonzalez have received online death threats since Gonzalez surrendered to police Tuesday. They have left Gonzalez shaken up, he said.

"He doesn't understand why there's such a public outcry against him when not all of the facts have been released yet," he said.

Gonzalez and the 16-year-old return to family court court Feb. 25.

Myles Ma may be reached at mma@njadvancemedia.com. Follow him on Twitter @MylesMaNJ. Find NJ.com on Facebook.