LAS VEGAS >> A Las Vegas man who has been free on bail for three months while fighting explosives and firearms charges was arrested late Wednesday on counts of terrorism and possession of weapons of mass destruction, authorities said.

Nicolai Howard Mork’s defense attorney,Nicholas Wooldridge, expressed shock at the two new charges against his 40-year-old client in Nevada state court, and the $8 million bail amount set by a judge who issued a warrant for his arrest.

Mork had posted $220,000 bail following his arrest in December.

Mork was taken into custody at one of his homes in a southern Las Vegas neighborhood after police evacuated residents from several nearby homes, police Sgt. Jeff Clark said. He called the evacuations a precautionary move.

Mork legally possessed materials commonly used for targets that can explode when shot during firearms target practice, his lawyer said,

Woolridge said similar devices are commercially available and not prohibited under federal law.

Deputy Las Vegas Police Chief Chris Jones declined to specify the materials that police seized Dec. 29 with a search warrant at Mork’s home.

Mork was arrested at the time on charges that he illegally possessed explosives, a silencer and a gun with a serial number removed.

“The manner in which this individual was using these materials was not for legal purposes,” Jones said. “These substances could be used in the manufacture of powerful explosive devices. The more you use, the larger the device, the more destructive it’s going to be.”

Chief Deputy Clark County District Attorney Jacob Villani said the chemicals were strong enough to penetrate a military tank, the Las Vegas Review-Journal reported (http://bit.ly/2nFaXqJ).

Woolridge disputed the newspaper’s characterization of Mork as a theoretical mathematics graduate from the Massachusetts Institute of Technology. Woolridge said his client had a master’s in business administration from the school.

An FBI spokeswoman in Las Vegas said the bureau wasn’t involved in the case. Officials at several gun stores and a public gun range in Las Vegas declined to comment about the commercial availability of explosive targets.

Jones, who heads the police department’s Homeland Security unit, said the investigation arose after several explosions in two neighborhoods where Mork lived, and complaints by neighbors about damage to their property.

“Devices had either exploded or were found unexploded,” Jones said. “They clearly were not being used for legal purposes.”

Clark County District Court Judge Douglas Herndon ruled that because of the seriousness of the charges, Mork will have to show the source of money used for his bail.