LAS VEGAS (KLAS) — A teenager accused of planning a terror attack in Las Vegas was allegedly building bombs in his room and may have been preparing to target a school, according to documents the 8 News Now Investigators obtained.

Joshua Robles was 16 when Las Vegas Metro police arrested him in late November. Because of his age at the time, the courts and police kept Robles’ name and details about his arrest confidential. Earlier this month, a judge certified Robles as an adult before a Clark County grand jury indicted him on terror-related charges, including providing material support for acts of terrorism or terrorists and attempting to commit or cause an act of terrorism.

In late November, a person submitted a tip about Robles, saying he was allegedly posting online about supporting the Islamic State, documents said.

“Peace by [sic] upon all brothers who see this,” Robles wrote in one post, according to police. “I am here to announce that I will be starting lone wolf operations in Las Vegas against the enemies of Allah.”

Detectives tied the post back to Robles’ North Las Vegas residence, documents said, adding at least one post contained ISIS-inspired imagery. Police later found other online posts, which they said indicated Robles “likely [supported] ISIS and the use of violence in support of ISIS’s goals,” documents said.

On Nov. 29, 2023, police raided Robles’ home finding components they said could be used to make an explosive device. Specifically, police believe Robles was building explosive devices similar to the ones that killed three and injured hundreds in the 2013 Boston Marathon bombing. Police suspect Robles may have been interested in carrying out an arson attack on Jan. 1, 2024, they said. Documents indicate Robles was searching for information and floorplans for Chaparral High School in the east valley.

Police also found a passage in a notebook about “The Islamic State-Las Vegas Province” and using improvised attacks, documents said.

During an interview with police, Robles said “he did not intend to carry out an attack” but was posting to “troll” other users, documents said.

During a news conference announcing Robles’ arrest in November, police said they found terrorism propaganda, a handmade ISIS flag, a headband and patches in Robles’ home. Evidence also included ISIS and Al-Qaida propaganda, radicalization materials, and guidance for conducting a terrorist attack, investigators said. Police also found self-portraits of the suspect wearing the material and surrounded by propaganda, self-produced terrorism propaganda and anti-Semitic threats, they said.

In court last week, Pro Temp Judge Lauren Diefenbach set Robles’ bail at $10,000. Prosecutors argued for Diefenbach to set the amount at $1 million. Following Robles’ grand jury indictment, a district court judge reset Robles’ bail at $1 million. A judge could readdress bail on Wednesday.