(NewsNation) — A Michigan man is facing criminal charges after planning to plant explosive devices in the Satanic Temple in Salem, Massachusetts.

Luke Isaac Terpstra, 30, of Grant, Michigan, was arrested Jan. 2 and charged with possession of explosives with unlawful intent, according to the Salem Police Department.

Salem police say Terpstra traveled to Salem at some point in November, possibly to plan for the attack.

“There is currently no indication that he had local allies in Salem or that he acted with any accomplices,” the Salem Police Department wrote in a statement. “On the one hand it is gratifying that our federal and local partners were able to thwart Terpstra. On the other, it is terrifying that he walked in our midst planning such violence.”

The statement also stressed that those in the public must alert the police if they see anything suspicious or learn of any threats.

“It is for this reason, we maintain a presence on the Joint Terrorist Task Force (JTTF), we maintain an explosive ordinance detection K9, we participate with our partner agencies in the Northeastern Massachusetts Law Enforcement Council (NEMLEC), we train our officers for such an attack, and we carry additional armor in our cars. Regardless, an attack such as Terpstra was planning keeps us up at night,” the Salem police said.

An investigation by Michigan State Police and the FBI is ongoing.