I've never been one of those "black helicopter" guys. You know, the conspiracy theorists who see government secrecy and snooping around every corner.

Well, at least I wasn't until I actually saw the black helicopters.

I heard them first: a heavy thumping that rattled my condo windows as they darted like bats through the valley of apartment complexes near Loring Park. Over and over.

Like a lot of other residents of the Twin Cities, I had spent part of the night watching scenes from Ferguson, Mo., where police using military gear and weapons went after demonstrators and reporters with rubber bullets and tear gas.

The exercises, coupled with this newspaper's story last week about tons of military equipment being given to police departments, including a grenade launcher to tiny Royalton, are disconcerting. Sen. Claire McCaskill, chair of the Homeland Security and Government Affairs Committee, is concerned enough to plan hearings soon.

The helicopters creeped me out, and I wasn't alone. I know the exercise was planned months in advance, but the timing was terrible.

The military unit was the Night Stalkers, an Army regiment that specializes in night missions using Blackhawk helicopters, and it does these exercises in several cities each year.

If this week's maneuvers were similar to those that happened here in 2012, the secrecy was intentional.

The nonprofit watchdog Public Record Media obtained 2012 agreements and mail between the Navy and Twin Cities officials that shed light on what likely happened this week.

The 2012 agreements allowed the military to conduct "low visibility movement, military operations in urban terrain, manual and low weight explosive breaching, low-altitude precision helicopter operations, live fire, simunitions; flash bang and surveillance."

Those documents show that Minneapolis purposely found a way around notifying the City Council by using the city's water works plant to give permission for the training.

"Documents indicate that the city was sensitive to publicity about the exercises, and sought to enter into a contract without City Council process so as to keep the training out of the public eye," PRM found.

Navy attorney Billy Holt wrote to Corey Conover, an assistant city attorney: "That's great news that this will hopefully allow your client to sign without placing this before the City Council."

Both cities' mayors, R.T. Rybak and Chris Coleman, were aware of the 2012 maneuvers and even wrote cheery welcome letters.

The documents, however, also show significant concerns about public safety.

"If a helicopter crashes into a softening plant killing 10 people, seven employees and three visitors, shouldn't they protect us from all liability, whether or not they were negligent? I'm not expecting they will be willing to do that," Conover wrote.

Minneapolis eventually got the Navy to agree to stricter liability terms, something Matt Ehling, PRM's president, commends.

Ehling said there were some "weird, unanswered questions" about the 2012 actions.

Some communications were redacted, and some language in the agreements suggested that the cities were concerned that activities captured by surveillance technology by the military would be turned over to the local police.

"Licensor grants consent to the licensee to collect overhead imagery and remote sensing data," the contract read. "This collection will not be utilized to support local, state or federal law enforcement investigations."

In other words, if choppers were over your house in 2012, you may be on candid camera. The military pinkie promises not to turn it over to local authorities, however.

The St. Paul attorney's office also expressed concerns about use of private property and "invasion of privacy of third parties."

Ehling said Minneapolis' stipulation appears directed at the Posse Comitatus Act, a federal law that prohibits the military from direct local law enforcement activities.

The act discouraged President George Bush from sending the military in to capture suspected terrorists in Buffalo, N.Y. He sent the FBI instead.

"There's a place for the military and a place for practicing these kinds of tactics," said Ehling. "But we have to be really careful of blurring these kinds of lines."

The issue of the military training in a civilian environment poses one set of questions, those about proper notice, transparency, safety and input from elected officials, Ehling said.

The issue of civilian police acquiring military gear, and participating in military training to bring those techniques home for domestic deployment, raises another set of questions, such as use of force protocols, he said.

John Elder, Minneapolis police spokesman, said the local officers were there for "logistical support" and to keep citizens from training scenes.

I asked him if there was any discussion to perhaps postpone the exercises because of the tensions caused by Ferguson.

Elder said there is almost always some incident happening in the country that might cause concern, and "at what point are you losing a lot of money by pulling the pin?"

Elder said the exercises had been planned for two years.

That doesn't comfort Hans and Barb Gasterland, who were in their house in Bryn Mawr when they heard a loud explosion coming from the Fruen Mill near Bassett Creek. "This explosion was much bigger than the fireworks you see downtown," said Hans. "It was a bigger explosion than you should have to worry about without being warned."

So big it knocked a clock from an easel onto the floor.

"Our threshold of fear is probably lower here because of the Accent Signage shootings," said Gasterland.

In 2012, a disgruntled employee killed several co-workers in the state's deadliest workplace shooting.

The Gasterlands are close enough to the company that a worker fleeing the gunman ran through their yard.

Gasterland said this week's explosions at the mill were attended by police and the military, but he's not sure who was participating.

"Only the military knows what the military knows," he said.

The good news, I guess, is that if the military collected information on you during the fly-bys, it won't be used, at least by local authorities.

And if a helicopter had flown into your house, the city was off the hook.

Make you feel better?

jtevlin@startribune.com • 612-673-1702