CEDAR RAPIDS - When Matthew Dummermuth was growing up in rural Northeast Iowa, he didn't notice a lot of crime.

But in the past three years, he has seen more than his share of violence, drugs and theft as the top federal prosecutor for the northern half of Iowa.

Dummermuth stepped down this week from his tenure to make way for incoming U.S. Attorney Stephanie Rose.

He called the experience "eye-opening" and said it was a privilege to be able to return to Iowa to fight federal crime after a stint with the U.S. Department of Justice's civil rights division in Virginia.

"It has been a rewarding challenge to seek justice each day in each case for every defendant, every victim and every member of the public," the soft-spoken Dummermuth said.

Among his top accomplishments, Dummermuth listed the prosecution of child molesters, often for finding victims over the internet. He was a member of a group of prosecutors that dealt with child exploitation for the Attorney General's Advisory Committee.

In the past five years, there have been federal child exploitation or enticement cases in 26 of the 52 counties that make up Iowa's northern district. Ages of those charged have ranged from 20s to 70s with an array of occupations.

"We're seeing it all over," Dummermuth said.

The worst example was a Dubuque case where the suspect was charged with abusing a boy he met in an Internet chat room. The investigation that followed determined he had done the same to 13 others, aged 14 to 16, from three states.

On a related matter, Dummermuth's office was heavily involved in the prevention side of the issue. He and his staff have traveled to almost 150 schools in northern Iowa to deliver presentations to 42,000 students on the dangers posed by online predators.

The largest and most controversial case Dummermuth oversaw was the immigration and fraud investigation of the former Agriprocessors meat packing plant in Postville.

Because sentencing in the matter is pending, Dummermuth wasn't able to discuss the matter.

It was the largest single-workplace immigration raid, detaining some 389 illegal workers. Eight management and supervisory employees were prosecuted, and former executive Sholom Rubashkin was convicted of 86 fraud-related charges. He is facing up to 1,255 years in prison.

The office also pursued other notable fraud cases in Northeast Iowa, including rogue insurance agent Jack Straw, who was sentenced to 15 years in prison for bilking elderly investors of about $3 million.

Criminal drug cases worked by Dummermuth's office varied from multidefendant methamphetamine labs who use a network to "smurf" cold pills and other ingredients to online pharmacies that employed doctors to crank out prescriptions based on Internet consultations with patients.

In the pharmacy case - where three customers died - the government seized $7 million in proceeds and handed over $4 million to Iowa law enforcement agencies.

On the civil side, Dummermuth's office signed a $4.5 million settlement with Covenant Medical Center in Waterloo over allegations of improper compensation arrangements with its doctors.

Dummermuth, an Elgin native, started off as an agricultural engineering major at Iowa State University. He became interested in law and public service after working for a state representative during the debate over capital punishment. He also interned for Sen. Charles Grassley.

He clerked for Judge David Hansen with for the Eighth Circuit Court of Appeals and joined a private law firm in Cedar Rapids after receiving his law degree from Harvard.

He joined the U.S. Department of Justice about seven years ago and was appointed U.S. Attorney for the Northern District of Iowa in January 2007 by then President George Bush.

Dummermuth is weighing his employment options, possibly as in-house counsel for a law firm.

"I enjoyed public service, so I'll explore those as well," he said.

For the immediate future, he and his wife, Becky, are expecting their third child. He plans to return to his parent's farm to help with chores.