SIOUX CITY | As forensic investigation techniques get more advanced, police investigators are finding them ever more useful in solving crimes. A new law set to take effect in Iowa later this year could help law enforcement officers even more.

Beginning July 1, offenders convicted of most aggravated misdemeanors in Iowa's courts will be required to submit a DNA sample. Current law requires felony convicts as well as sexually violent predators and sex offenders to submit DNA samples.

When he signed the bill into law in May, Gov. Terry Branstad said it will help police solve crimes and possibly exonerate suspects who have been falsely accused.

He'll get no arguments from law enforcement.

"It's going to definitely aid in getting people involved in crimes off the street. I think it's going to be a big help for us solving crimes," said Sgt. Pat Breyfogle, an investigator in the Sioux City Police Department's crimes against persons unit.

Juveniles will be exempt from the new requirement. Aggravated misdemeanors related to gambling, hazardous waste, agriculture productions and many traffic offenses also will be exempt from the DNA submission.

Breyfogle said common aggravated misdemeanors are assaults and burglaries. Burglaries can be hard to solve, but it's not uncommon to find DNA evidence at the scene: a cigarette butt or blood on broken glass.

Zac Chwirka, Sioux City Police identification and property supervisor, said the law will expand the statewide DNA database and improve chances that DNA collected at a crime scene will match someone already on file. Other state labs can tap into Iowa's database, which is helpful when dealing with Sioux City crime suspects who live in Nebraska or South Dakota.

"This is just a very crucial tool for law enforcement to try to identify suspects," Chwirka said.

That DNA database can help solve crimes from long ago, Chwirka said. He remembers a Sioux City robbery and rape case from around 2000 in which police obtained DNA evidence of the perpetrator, but had no matches. The suspect was later sentenced for an unrelated felony, and when he gave a DNA sample in prison, the database matched him to the rape case.

"This is a huge tool for us to solve current and past crimes," Chwirka said.

The new law goes too far, some say. Rita Bettis, of the American Civil Liberties Union of Iowa, said the law expands DNA collections from cases that have a rational relationship to DNA -- sex-related crime and other felonies -- to lower-level, nonviolent offenses.

"The rationale that it will solve more cases is absurd when applied to these types of cases," Bettis said. "Under that rationale, the state could collect DNA from everyone at birth and store it long after their deaths. The government's interest in solving crimes must be balanced with the people's fundamental freedoms.

"We think it's invasive and unnecessary."

Breyfogle dismissed concerns about expanding the DNA database to include those convicted of less-serious offenses.

"It's really no different than having your fingerprints on file," he said.

Collecting those additional samples shouldn't be a problem, said Steve Scholl, director of corrections in Iowa's 3rd Judicial District. Most offenders convicted of aggravated misdemeanors likely will be placed on probation rather than sentenced to prison, so probation officers will collect their samples.

Scholl said it will take a little extra time for a probation officer to swab an offender, then seal and send the sample to the crime lab, but it won't lead to any extra expenses in his budget.

Woodbury County Attorney Patrick Jennings said he hoped the new law could act as a deterrent as well as help gain convictions. DNA evidence can be extremely helpful to convince juries, but it's also not necessary if the case's other facts are strong.

"Depending on the facts of the particular case, the lack of forensic evidence doesn't necessarily mean the prosecutor's case is doomed," Jennings said.

For police, DNA is considered one piece of solid evidence that can make a case.

"DNA assists in a lot of cases. Frankly, there's probably a lot of cases that are brought to trial or charged because of DNA evidence," Breyfogle said.