LEWISTON — Children who grow up in poverty are more likely to be involved in crime, a group calling for  anti-poverty legislation said Thursday.

And the Twin Cities have the highest rates in the state for children in poverty: Lewiston at 42 percent; Auburn at 27 percent.

At a joint news conference at the Lewiston police station, law enforcement officials teamed up with the regional director of Fight Crime: Invest in Kids to call for extending federal child tax credits, available to low-income families. The tax credits are due to expire at the end of the year.

As many as 60,000 Maine children could be affected if the legislation isn’t passed, the speakers said.

New research shows that raising children out of poverty reduces the crime rate, said Kim Gore, New England director of the group.

“Our mission is to prevent crime and violence across the United States by making wise investments in programs that keep kids safe and give kids the right start in life,” she said.

Waiting until a child is arrested is too late, she said.

“Research shows that when you increase the income for low-income families, it substantially reduces those difficult youth behaviors that are often the precursors to later crime,” she said. “The child tax credit lets low-income working families keep more of their tax dollars, raises their standard of living and it reduces the probability that the children might be involved in crime later on.”

Deputy Chief James Minkowsky of the Lewiston Police Department said most children who grow up poor don’t go on to lead lives of crime. But they run a greater risk of becoming adult criminals, he said.

Androscoggin County Sheriff Guy Desjardins said at least one in six children in Maine is living in poverty, placing them at “substantial” risk.

From October 2008 to May 2010, the state’s unemployment rate has climbed from 5.9 percent to 8 percent.

Children in families whose income has climbed above the poverty level experience a 40 percent decrease in conduct disorders and opposition defiance disorders, according to a study, Desjardins said.

Those behavior disorders are “closely linked” to juvenile crime, he said.

Auburn Police Chief Phil Crowell said the county’s jail population tells the same story: The demographics support the notion that children from poor families are more likely to end up in the criminal justice system.

Pulling children out of poverty not only benefits those children but society as a whole, he said.

For every $1 spent on early childhood education, there is a return of $18 million in savings from avoiding incarceration, Crowell said.

The nonprofit group includes 120 Maine members, including every sheriff and prosecutor as well as about 90 police chiefs and survivors of violent crimes.