A Pennsylvania teenager suspected of trying to help the Islamic State, also known as ISIS, appeared in court on Wednesday and was ordered to remain in custody.

Federal prosecutors accuse Jalil Ibn Ameer Aziz, a 19-year-old U.S. citizen from Harrisburg, of using Twitter to advocate violence against the U.S., in support of ISIS, and provide the notorious terror group with helpful information. He was arrested on Dec. 17, just weeks after FBI agents found high-capacity magazines in what was described as a "tactical-style backpack" in his bedroom during a search of his home on Nov. 27.

During his detention hearing and arraignment on Wednesday, a U.S. District Court judge ordered Aziz to stay in jail, calling him a danger to the public and a flight risk, reports The Associated Press. The teen, who is being held on charges of conspiracy and trying to help a foreign terrorist organization, pleaded not guilty.

According to prosecutors, Aziz possessed a "go bag" that contained ammunition for an assault rifle, a knife and a black mask.

"The evidence is extremely strong," said Assistant U.S. Attorney Daryl Bloom. "We know that he wants to kill all unbelievers."

Bloom added that Jalil had placed 100 people on a "kill list" that included their addresses and personal information, reports Reuters.

His public defender, however, dismissed the evidence being presented against her client by the U.S. Justice Department.

"The government calls it a 'go bag,'" argued attorney Lori Ulrich. "It was a backpack. There were no firearms in the house capable of firing that ammunition."

She also noted that Jalil did not have a criminal record, passport, money or resources to help terrorists. She called his Twitter activity in support of Islamic State "independent advocacy."

If found guilty, the teenager could be sentenced to up to 40 years behind bars.