The arrests of three suspected terrorists Friday in Germany are significant, according to U.S. officials, who say at least one member of the trio was trained by al-Qaida – not merely inspired by the terrorist organization.

The three men arrested in and around Duesseldorf, all German nationals, had been under surveillance for some time, and that U.S. intelligence cooperated with German authorities in the investigation, said one U.S. official, who spoke with NBC News on condition of anonymity. The official added that the men had already put together "precursor chemicals" for a terror attack and were planning a "test run" on Friday morning. Although the test was postponed, German authorities decided to move in and arrest them, the official said.

U.S. officials described the planned target as "localized" and related to "public transportation, trains or buses." The official would not comment when asked if U.S. servicemen might have been targeted. Public transportation has become a primary target of al-Qaida and other terrorist groups in the years since the Sept. 11, 2001, terror attacks in the United States, with more than 800 people killed around the world, from London to Mumbai to Moscow, in the past five years.

Neither U.S. nor German authorities would identify the suspects, but German security officials said all three were of Moroccan origin.

The U.S. official said one of the three had recently been trained along the Pakistan-Afghanistan border by people associated with “al-Qaida Central” -- the term used by U.S. intelligence to describe the organization's core group operating in the border area.

"As it unfolds, it will be shown they are al-Qaida. One was trained in Pakistan, in the tribal areas of Pakistan," the official said.

"This was well beyond aspirational," the official added. "The police had been watching for some time, watching and monitoring, planning on disrupting it at the right time."

The official said the investigation was continuing and that other arrests were possible.

Germany has escaped any large-scale attack by an Islamic terror organization, such as the Madrid train bombings of 2004 and the London transit attacks of 2005. But Germany's presence as part of the NATO coalition in Afghanistan has sparked anger and at least two major plots have been thwarted or failed in Germany before they could be carried out.

Asked if this plot was behind the general alert in Germany last summer and fall, the official said the alert was "generated by these types of plots", but not specifically this plot. "We are seeing these in Europe every few months," the official added.

German Interior Minister Hans-Peter Friedrich said Friday that the arrest of three suspected Islamic extremists  had averted  “concrete and imminent danger” of a terrorist attack in Germany.

The three men are scheduled to appear at a court hearing in Karlsruhe, Germany, on Saturday.

The Associated Press contributed to this report.

Michael Stravato / for msnbc.com

Sandra and Shanoop Kothari of Houston hold a photo of their two children, Hannah and Harrison. After a routine surgery for a benign cyst, Harrison Kothari, 2, died last year of bacterial meningitis caused by Bacillus cereus, a rare bacterium that was later linked to the recall of millions of alcohol prep wipes.

Here’s a medical horror story for you: What happens when the very products used to protect sick people against infection and illness turn out to be contaminated with potentially deadly bacteria?

That’s the situation msnbc.com has been investigating since mid-February, when first reports emerged that alcohol prep pads widely used in hospitals and clinics, and sold in most major drugstores in America, might be tainted with bad bugs.

The alcohol wipes were made and distributed by H&P Industries Inc. and the Triad Group of Hartland, Wis., which launched a voluntary recall out of what the firm’s owners said was simply an abundance of caution.

Four months later, amid lawsuits alleging infection and death, the federal Food and Drug Administration last week asked U.S. marshals to shut down the firm and seize more than $6 million worth of medical products.

That move came after dogged reporting by JoNel Aleccia, health reporter for the news website msnbc.com. She reported that the FDA knew as far back as 2009 about problems with contamination at the company’s plant, but that agency officials failed to take aggressive action, contending that there was no imminent public health hazard. In a series of special reports, she has consistently been ahead of the pack on this story.

Open Channel asked Aleccia a few questions about her coverage.

Q. This issue was first raised in February by a Houston family who blamed the death of their 2-year-old son on contaminated alcohol prep pads that were later recalled.  At the time, it seemed like just one tragic case. When did it become a bigger story?

msnbc.com

JoNel Aleccia, msnbc.com health reporter

JoNel Aleccia:  While we were aware that alcohol prep pads had been recalled, we didn’t know the problem was serious until we heard from the family of Harrison Kothari, the Texas toddler whose parents claim died from the same bacteria that contaminated the wipes, Bacillus cereus.

That story led to other potential victims, and then to documents supplied by a confidential source that showed the FDA knew about contamination and sterilization problems at this plant dating back to 2009.

Q. But you’re talking about only a few reported infections and, sadly, one death. Why should the general public care?

Aleccia: The question here is not just the infections we know about, but the ones we don’t. So far, this company has recalled nearly a million cases of alcohol prep pads, hundreds of millions of individual wipes used in hospitals, clinics and in private homes by people who must take medications regularly. One Colorado hospital used 2,500 Triad wipes every day, and its analysis found that 40 of 60 wipes tested -- two thirds -- were contaminated with Bacillus cereus. Two children developed life-threatening infections, one child with leukemia and an infant with heart problems.

Investigators also have recalled tens of thousands of povidone iodine wipes made by H&P Industries, and those wipes are used not only to cleanse skin for minor infections but also to prep skin for surgery. The FDA says tests show the wipes were contaminated with different bacteria, Elizabethkingia meningoseptica. And now FDA officials say they’ve detected more “opportunistic pathogens,” though they won’t say which ones.

In addition, the company has recalled lubricating jelly used in medical exams, and there are reports of problems with a wide range of intimate care products, including acne pads, laxatives and children’s cold medicine. These items could be in anyone’s bathroom cupboard.

Q. How have you been able to follow the story so closely?

Aleccia: We’ve been able to track the story with basic reporting techniques, asking questions and following up leads as they arise. When the FDA said a report from a Colorado hospital led to the first recalls, but wouldn’t reveal which hospital, we called state public health officials to confirm the hospital and the doctors and then asked them to tell their story.

We’ve also been helped by sources who provided crucial documents. We got 2009 and 2010 government inspection documents known as Form 483s from one source and then confirmed that those documents were legitimate by getting duplicate copies from a great FDA monitoring site: FDAzilla.com. We got an internal company letter from a confidential source, and then confirmed it by getting a duplicate copy from a separate, independent source.

We’ve also been pretty vigilant with the FDA, asking them repeatedly to explain why a plant with such serious issues did not receive a warning letter or other sanctions – including product seizure or court action – until two U.S. senators intervened last month, asking FDA to account for its actions.

Q. What does the company say?

Aleccia: We’ve offered Eric Haertle, co-owner of H&P Industries, many chances to comment, with limited response. A newly hired company spokeswoman, Christy Maginn, confirmed the U.S. marshals arrived at the plant with seizure orders. She referred us to a statement that says the company believes its products remain safe.  “We are aware of no confirmed link between any H&P Industries Inc. product and patient illness or death.”

Q. What might happen next?

Aleccia: For now, the products remain quarantined at the Wisconsin plant under court custody. In similar situations, the FDA and the Department of Justice have launched criminal probes into contaminated products that have endangered public safety. Criminal investigations followed recent massive outbreaks of salmonella infections traced to tainted eggs and peanut butter, for instance.

Q. Have other media been following this story?

Aleccia: The Milwaukee Journal Sentinel newspaper has tracked this situation as a local story, but other national media outlets have limited their coverage mostly to following our reports of the $6 million product seizure last week.

Full coverage
Here are the full links to Aleccia's coverage on msnbc.com, tracing the arc of the story so far:

Feb. 15: Parents blame toddler's death on tainted alcohol wipes.

Feb. 22: FDA knew of problems at plant that made tainted wipes.

Feb. 25: FDA defends actions at plant that made tainted wipes.

March 7: Colorado hospital blew whistle on contaminated wipes.

March 11: Under pressure, firm shutters line that made tainted wipes.

March 18: Deadly infection risk triggers new recall from embattled medical supply maker.

March 24: Two-thirds of alcohol wipes in test contaminated with bacteria.

March 28: FDA asks maker of tainted wipes to stop production.

March 31: Senators question FDA's response to tainted wipes.

April 4: Wipe-maker shuts doors after US marshals arrive on site.

April 6: Feds seize $6 million in products from wipe-maker.

Do you have more information?
Send an e-mail to msnbc.com health reporter JoNel Aleccia.

The U.S. Nuclear Regulatory Commission announced Monday afternoon that it was investigating the "unplanned radiation exposures" of three workers on April 3, a week earlier, at the Cooper Nuclear Station near Brownville, Neb.

The NRC said it did not believe the exposure exceeded its limits.

"Workers removed a long tube contaminated with highly radioactive material through the bottom of the reactor vessel, rather than through the top as is usually done, triggering radiation alarms," the NRC reported. "The workers set the tube down and immediately left the area."

The Cooper plant has a single boiling-water reactor of General Electric design. (GE is a part owner of NBCUniversal, which owns half of msnbc.com.)

Here's a map of the plant, which is about 25 miles from Nebraska City, Neb., and south of Omaha.

The full release from the NRC:

NRC SENDS SPECIAL INSPECTION TEAM TO COOPER NUCLEAR STATION

The U.S. Nuclear Regulatory Commission has begun a special inspection at the Cooper Nuclear Station to review the circumstances surrounding a maintenance procedure that led to unplanned radiation exposures to three workers. The plant, located near Brownville, Neb., is operated by the Nebraska Public Power District (NPPD).

Inspectors, who began their work Monday, will look at the circumstances and decision-making by NPPD officials that led to the exposures, review the licensee’s response to the event, calculate the exposures the workers received and review corrective actions taken to prevent a recurrence.

The incident occurred on April 3, when workers removed a long tube contaminated with highly radioactive material through the bottom of the reactor vessel, rather than through the top as is usually done, triggering radiation alarms. The workers set the tube down and immediately left the area. The licensee does not believe the workers received radiation exposures in excess of NRC limits.

“We want to understand why normal work practices were not followed, resulting in unplanned radiation exposures to three workers,” said Region IV Administrator Elmo E. Collins. “We want to take a look at the decision-making that contributed to this event.”

The team consisting of two NRC inspectors, began work Monday and will probably spend several days at the plant. They will write an inspection report on their findings within 45 days of the end of the inspection that will be made publicly available.

The reporters and editors could hardly believe what they were hearing.

Over the past four months, NBC News investigative reporters have explored the trafficking of sex slaves in Latino brothels in the United States.

"It has been a story where the more we learned, the more we realized what we didn’t know," wrote NBC correspondent Richard Lui.

"In our editorial meetings, it was common for my editor to simply stare at me and say he did not believe what I was saying."

Here are links to the full series, Enslaved in America:

Stories
Azriel James Relph, The sex slaves next door. New form of trafficking invades US.

Richard Lui, A story both sordid and unbelievable. The spread of Latino brothels across the US has been silent but steady.

Sandra Lilley, Victims of the unimaginable speak out. Women rescued from Atlanta brothel recount trauma and abuse, caution others.

Graphics
Map: Latino residential brothels spread nationally.

Interactive: How the sex slave supply chain feeds the U.S. market.

Slide show: Breaking the code: Common practices at brothels.

Videos
See all the videos at this link, including Web-only exclusives.