Massachusetts Man Wanted to Attack Mosque and Kill Obama, FBI Says Suspect allegedly had a "trove" of weapons.

 -- A Massachusetts man, already under FBI investigation, was arrested over the weekend and charged with weapons possession after allegedly telling a childhood friend that he wanted to attack a mosque or kill President Obama, or do both, according to the U.S. Attorney’s Office.

Joseph Garguilo, 40, was arrested early Saturday morning in connection with the possession of a “trove of weapons” in violation of a restraining order, ammunition and incendiary material, as well as his threats to use them, according to the U.S. Attorney.

He allegedly told the friend he wanted to “chain a mosque closed and burn it down. Burn every [person] down in there,” according to court records.

Another person also reported him to the FBI on July 27, the charging documents allege. That person feared he was using drugs, acquiring parts to make an AR-15 and stockpiling other weapons, food and water because “Garguilo believes that the structure of America will collapse and that America is going to enter a state of martial law,” the court records state.

When martial law is declared, Garguilo told his children, he hopes to build thermite grenades to kill police officers, according to the documents.

That person also told the FBI that “he will plant bombs in police stations … and kill as many homeland security officers as he can before they kill him,” according to court documents.

The childhood friend also called the FBI to say he saw in Garguilo’s basement a partially assembled AR-15, crossbow and knives, according to the court records.

The friend told the FBI Garguilo said he wanted to “attack a mosque and/or kill President Obama,” according to the court records. He also said Garguilo’s “mental state had gone downhill,” the documents state.

The friend also reported that Garguilo made a comment to the effect that when Obama was on the golf course in Martha's Vineyard, Garguilo should have taken the opportunity to kill him, according to court documents.

The United States Secret Service is aware of the arrest and referred questions to the FBI.

When agents searched Garguilo’s residence last Friday they found ammunition, magazines, parts to assemble AR-15 rifles and chemicals that could be combined to create explosive material, according to the criminal complaint.

Agents also recovered handwritten notes allegedly threatening violence against Muslims.

Garguilo was taken into custody Saturday and had an initial court appearance Monday. He was charged with possessing ammunition in violation of the restraining order. He did not enter a plea, but plans to plead not guilty, according to his attorney, Mark Meehan.

Meehan said Garguilo is, "first and foremost, a loving and dedicated father to his two boys."

"[T]he character the media is portraying Mr. Garguilo as being is not accurate,” the lawyer told ABC News in a statement. “Mr. Garguilo, from what I am aware of, has never entertained any plots against any individual or group. Mr. Garguilo may not possess mainstream political beliefs, but what beliefs he does hold is no threat. He is a collector of self-defense tools and can be categorized as what is called a 'prepper,’ that is, preparing for difficult times.”

The FBI discovered that Garguilo has a criminal history with a number of “sealed adult appearances,” according to the court records. The status of an earlier conviction was unclear, according to the FBI.

As a result of the information the FBI received, it contacted the Holliston Police Department in Massachusetts. Detectives there were familiar with Garguilo and said they believed he had been involved in some kind of hit-and-run incident, according to court records.

Detectives also said that Garguilo had metal bars on his doors and windows, wears a handcuff key on his neck and is believed to abuse prescription medication, the documents state.

The restraining order required that he surrender all firearms and ammunition to police based on the finding that there “there is a substantial likelihood of immediate danger of abuse...”

A detention hearing is scheduled for Garguilo on Sept. 7. He is in the custody of the U.S. Marshals Service, according to the U.S. Attorney's office.