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An MIT graduate was arrested on charges of terrorism and possession of weapons of mass destruction, authorities said late Wednesday — and his mother told NBC News she believes her son suffered a "mental breakdown."

Nicolai Howard Mork, 40, was indicted by a grand jury on Wednesday in Las Vegas on charges related to terrorism and weapons of mass destruction, Las Vegas police said. He was arrested without incident at his home Wednesday night, police said.

Bail was set a $1 million per count, for a total of $8 million, according to court documents.

Mork is accused of planting several incendiary devices, such as Molotov cocktails, to be ignited in multiple locations in the Las Vegas area from Oct. 24 to Dec. 31, 2016, according to the indictment. He was also charged with possessing components of an incendiary device with the intent to manufacture an explosive, and with possessing a Walther P22 .22 caliber handgun with an altered serial number and a silencer.

Deputy Chief Chris Jones, director of the Las Vegas police Homeland Security Division, told NBC News on Thursday that investigators found at least eight explosive devices in two residential neighborhoods in Las Vegas beginning in late October.

"We started seeing this pattern as these devices were deployed and then similarities in the devices and the substances that they were constructed out of," he said.

"It appears that his actions were basically focused on grievances that he had based on perceived wrongdoings," Jones said. "He thought people were following him. He thought certain groups were following him."

Jones said some of the devices had "partially exploded, some had partially ignited and others were still intact." No one was hurt, he added.

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Mork's lawyer did not immediately respond to a request for comment.

The suspect's mother, Joan Mork, 70, told NBC News that she believed her son had suffered "some sort of mental breakdown" and that he was acting paranoid the last time she saw him.

"We believe that he has had some sort of mental breakdown or an enormous shift in his usual thinking, and we hope, with all our hearts, that he will get the help he needs and not just be punished," she said from her home in Duluth, Minnesota, on Thursday.

Nicolai Mork was charged with terror and weapons of mass destruction charges in Las Vegas. Las Vegas Police

"This is a young man — he's in his 40s now — but he was always brilliant and had many kinds of distinctions throughout his time and in our home and in college," she said.

She said that Mork was "extremely afraid and angry" with the Church of Scientology and that he believed he was being monitored by members of the group.

"He was extremely fixed on the notion that Scientologists were out for him and many others," she said.

The Church of Scientology told NBC News on Thursday night that Mork "has never had any relationship with the church." It claimed that it had received "more than 400 violent threats" after the recent broadcasts of TV programs critical of the church.

Joan Mork said that when she last saw her son, two years ago, "he was highly anxious" and "kept thinking that he was being recorded."

"He was very, very disturbed," she added.

Mork's mother said she and her husband urged their son to see a psychiatrist, but "he believed that what he was experiencing was all too real."

"He told us that we could believe him or stop being his parents," she said.

Mork's mother also said her son was always a star student in school and received a Master of Business Administration degree from the Sloan School of Management at the Massachusetts Institute of Technology.

"He has a mind that if it could be redeemed or saved in some way would really produce, I think, really great things," she said.

A spokeswoman for the school confirmed that Mork attended MIT from September 2002 to 2004 and graduated with an MBA.

According to the indictment, Mork's full list of charges comprises:

One count of an act of terrorism or attempted acts of terrorism

One count of unlawful acts related to weapons of mass destruction

Three counts of possession of a component of an explosive or incendiary device with intent to manufacture an explosive or incendiary device

One count of possession of an explosive or incendiary device

One count of possession of a firearm with an altered or obliterated serial number

One count of possession of a silencer

Mork was initially arrested in December and was out on bail after posting $220,000. NBC affiliate KSNV reported that Mork posted the cash bond on March 23, citing court documents.