Within the last week, United States officials have sorted through three cases of suspected terrorist activity — two closely linked with Michigan, though experts say there isn't an increased security threat.

Outside of the foiled terrorist plot to use chemicals as detonators on U.S.-bound flights from the United Kingdom, two men from Dearborn were arrested in Ohio with a bulk supply of cell phones.

Cell phones have been used to detonate bombs in terrorist attacks around the world, including a Madrid bombing in 2004.

The same suspicion led to the arrest of three Texas men in Caro found with a large number of cell phones and pictures of the Mackinac Bridge.

First Lt. Chuck Loader, section commander of the Michigan State Police Homeland Security, said the arrests of the terrorist suspects have led to a flood of information to process this week, all of which needs to be sifted through and acted upon, if necessary.

"The use of phones for criminal enterprise has been a long-time proven method," Loader said. "At the time, the officials involved made a prudent call."

He said people should know these were not targeted attacks, but reporting suspicious activity is how officials and citizens can work together to stop terrorist activity.

"We don't want to discourage people from calling — it's exactly what people should do. But yet at the same time, we want to alleviate fear," he said.

"We have no reason to believe anything in this country or in this state has been specifically targeted."

Special Agent Dawn Clenney, spokeswoman for the FBI in Detroit, said the agency was alerted by local officials to look into the Caro arrests, and the investigation will continue.

"As leads come in and we need to follow them up, we do so immediately — no matter where they take us, we are going to run these leads down," she said.

No federal charges have been filed, she said, adding that the foiled terrorist plot in the U.K. has increased the overall workload for the FBI.

David Carter, an MSU professor in the School of Criminal Justice, said similar situations have happened around the country, but because of the thwarted U.K. terror plot, everyone's radar is up, including the media.

Carter said he has received several millions of dollars in grants from the Department of Homeland Security to train law enforcement agencies across the state.

"It's a very methodical process of uncovering evidence," Carter said. "We base ourselves on what the evidence suggests to us, not jumping out and saying, 'Ah-ha.'"

Looking at the evidence without preconceived ideas is an important part of uncovering what really happened, he said.

"If you look at how cell phones are used by extremists, or terrorists, you don't need a thousand of them ? so the logical thing is they are trying to sell them and make money off them," Carter said, adding that he believed their intent was to sell the phones for profit.

He gave the example of the picture of the Mackinac Bridge. Many people have pictures of the bridge — perhaps a snapshot as they are driving by or are out touring. But if someone has a picture of the stress points of the bridge or traffic patterns, then there would be reason to look further into it.

Even then, he said, it could turn out to be an engineering student.

"So it almost becomes a frenzy sometimes," he said.

Since the Sept. 11 terrorist attacks, terrorism is immediately considered as a possible motive, whereas 10 years ago it wouldn't have been, Carter said.

Homeland Security has refined the color-coded advisory system to target specific areas of potential danger, Loader said. Right now the only heightened sector is commercial airlines. Flights coming out of the U.K. were moved up to red, a severe warning level, until Sunday evening and then went back to orange, or high, he said.

"I think it's important for people to feel at ease," Loader said. "Bottom line is we are all in this together."