"This happened last Sunday. The man was detained due to his suspicious activity outside the gurdwara. The police questioned him. Later it was determined that he was not a threat (to the gurdwara). So he was released," Oak Creek Mayor Steve Scaffidi told PTI.
In a report released on Thursday, the Oak Creek police department said the 32-year-old man from Maryland was found with 9mm ammunition and "strange writings" in his possession outside the Wisconsin gurdwara. He was seen entering the gurdwara premises at about 8:45 am.
The gurdwara was the scene of a mass shooting by a white supremacist in August that killed six Sikh worshippers, sending shock waves across the country and the Sikh community world over.
The man, whose identity has not been released, first told the police that he drive to gurdwara after seeing a CNN story about the shooting and wanted to pray with its members.
Later, he changed his version and said that he was writing a book and wanted to talk to the people there.
"Officers located a large amount of zip ties and a roll of duct tape in the backpack (of the man) as well as a notebook containing strange writings referencing the mass shooting in Aurora CO (where a gunman had killed 12 people inside a cinema hall) and a piece of crime scene tape collected from the scene in CO (Colorado)," the police report said.
"Officers also located more zip ties and duct tape, several boxes of 9mm ammunition in (the man's) vehicle along with gun cleaning supplies and an empty case from a Glock 9mm," the report said, adding that the Federal Bureau of Investigation was called when the man surrendered with his ammunition.
Thereafter, he was asked to follow officers back to the Oak Creek police station so that his writings and identification could be copied. "He was not arrested. He was only detained," Scaffidi said.