Southport resident Dane Eisenman, who police said was preparing for an alien invasion, was arrested on a warrant Thursday morning little more than a month after he paid cash for a .30-06 rifle advertised in a classified ad.

After the sale took place at the 57-year-old Eisenman's Sherwood Drive home, the Danbury resident who sold the rifle to Eisenman called police because Eisenman started talking about using the rifle to kill aliens, police said.

The seller initially thought Eisenman was joking, but Eisenman went on to say that every 30,000 years, aliens who live under the sun come to Earth to kill humans, so he plans to be prepared for them because "they're going to be coming soon."

After checking his background, police discovered that Eisenman is a convicted felon. As such, he is not allowed to own handguns or rifles.

Police issued a warrant for Eisenman's arrest, and he turned himself in about 11:15 a.m. Thursday on a charge of criminal possession of a firearm.

"Thank God for the seller being so astute, because this guy could have mistaken an innocent human being for an alien," said Sgt. Jim Perez, spokesman for Fairfield police. "This wasn't a Star Wars light saber he purchased. It was an extremely dangerous high-powered weapon."

Eisenman was released on a promise to appear July 9 in Bridgeport Superior Court.