An Arizona man indicted on terrorism-related charges may have been planning an attack in San Diego, according to federal documents.
A grand jury charged Mahin Khan, 18, with terrorism, conspiracy to commit terrorism and conspiracy to commit misconduct involving weapons on Wednesday after he was arrested last week at his family's Tucson home.
Authorities released the indictment -- which was the result of an FBI investigation -- on Thursday.
Authorities said Khan had written emails to an alleged member of the Pakistan Taliban seeking weapons and instructions for a homemade explosive. It's not clear if Khan was corresponding with an actual member of the violent organization also known as TTP, but a probable cause statement shows the FBI examined the emails.
In them, Khan said he backed the Islamic State group and was looking to carry out an attack. The person responded that he would have to pay for two assault rifles and a pistol he requested, so Khan said he wanted instructions for a bomb instead, the heavily redacted document says.
The FBI began investigating Khan after a citizen reported him for suspicious activity and were tracking him as he asked someone else on April 16 about targeting Mission Bay, and an Air Force recruitment center in Tucson, according to the probable cause statement. The identity of that person was redacted, but it was not the alleged Taliban member.
The indictment also revealed that Khan planned to bomb a Motor Vehicle Division office in Maricopa County, the Arizona's most populous county, between April 2015 and July 1, 2016. Mia Garcia, spokeswoman for the state attorney general's office, which is prosecuting the case, said she could not release more details about the plot.
The statement was written before Khan's arrest, and the plot against the motor vehicle office came to light after authorities searched his home. He was indicted in that plot because it appeared he took steps to carry it out, as opposed to his discussions against the other targets, authorities said, refusing to release further details.
Khan described himself as an "American Jihadist" on Feb. 22 and sent a picture of himself, saying he needed guns to "take out marines and jews."
Little information exists about Khan's past. Records show his family has lived in Tucson for several years and his father has a medical license.
He attended a high school in the Catalina Foothills School District for a few days in August 2013, district spokeswoman Julie Farbarik said. Khan had behavioral issues, and his parents withdrew him to avoid disciplinary action, she said.
A spokeswoman for the Tucson Unified School District said the district was closed and she could not to look up whether Khan had attended school there.
