A group of Minnesota parents has accused state and county child protection agencies of wrongfully removing their children and placing them in foster care for what they consider to be ordinary parental discipline, such as spanking.

In a civil rights lawsuit filed Tuesday, attorneys for the parents allege that Minnesota's child protection laws are overly broad, triggering unnecessary investigations and putting children at risk for being removed from safe and loving homes.

The main plaintiff in the case is Dwight D. Mitchell, who founded an association of parents called Stop Child Protection Services From Legally Kidnapping, which has about 250 members across the state. Mitchell alleges that two of his children were removed from his home in Apple Valley by Dakota County child protection workers after a family babysitter reported that his 11-year-old son had received a spanking from Mitchell for stealing and disobeying his parents.

"It was every parent's worst nightmare," said Mitchell, 57, a management consultant. "My children were legally kidnapped for a bottom spanking that was done out of love, because I want my children to grow up to be hardworking members of society."

The child, Xander Mitchell, was kept in state custody for 22 months, during which time his father was refused all contact. Mitchell's other child was removed for five months, according to the lawsuit filed in U.S. District Court in Minneapolis.

A spokeswoman for Dakota County declined to comment, saying the agency had not had a chance to review the lawsuit. A spokeswoman for the Minnesota Department of Human Services, which oversees the child protection system, also declined to comment, saying the agency had not been served with the lawsuit.

The case raises broader questions about what constitutes child abuse, and whether Minnesota laws wrongly criminalize parents for what many consider to be routine parental discipline. Under current state law, a child can be found to be "in need of child protection services" if a parent inflicts bodily harm, defined as causing any pain, injury or illness.

Based on this definition, any parent who inflicts harm — through spanking or hitting of any kind — could potentially have their children removed by child protection agencies. Even a threat of a physical injury can be interpreted as maltreatment under state law, the plaintiffs allege.

The lawsuit alleges that laws that allow child protection agencies to remove children for "ordinary corporal punishment," such as spanking, have a disproportionate impact on black families. In 2016, African-American children in Minnesota were more than three times more likely than white children to be "screened in" to the child protection system for review, according to a state report.

The issue became more prominent in 2014, after former Minnesota Vikings running back Adrian Peterson admitted to hitting his son, including with a belt and a tree branch, causing visible injuries. At the time, a Star Tribune poll found that corporal punishment is common among Minnesota households, with nearly 60 percent of adults saying their own parents used such punishment.

Other states, including Hawaii, Massachusetts, Oklahoma and Oregon, have enacted laws to protect a parent's use of corporal punishment from child protection investigation and proceedings. In Oklahoma, for instance, child protection workers are required to immediately cease investigations into reports of child maltreatment if it is determined that the report stemmed from "the reasonable exercise of parental discipline," including "spanking, switching, or paddling."

"I am not the only parent who thinks that the 30-year social experiment of removing corporal discipline from our homes and schools has gone too far," said Mitchell, who is black. "You look at all the school shootings and have to ask where it's gotten us. Kids have a total lack of respect for teachers and adults."

Mitchell said his involvement with child protection began on the night of Feb. 16, 2014, when he and his wife went to dinner and a movie and left their children in the care of their longtime babysitter. A day earlier, Xander had received a "bottom spanking" from his father for stealing and other acts of disobedience, including failing to do his homework and playing video games when he should have been sleeping.

When the babysitter called to report the alleged maltreatment of the child, police were dispatched to Mitchell's residence and his three children were taken to the police station for questioning, he said. Days later, Dakota County filed a court petition seeking protection for Mitchell's children, who were removed from his home and placed in foster care while the county investigated.

Mitchell said his son Xander, now 15, has never been the same since. The once-gregarious and athletic child, who loved soccer and skiing, has become increasingly introverted and now spends most of his time indoors, he said. "The abduction by child protection services ruined my son's life and changed it forever," Mitchell said. "Can you imagine if you thought that your father abandoned you?"

Rhia Bornmann Spears, a Minneapolis family law attorney and child welfare advocate, said Mitchell's case illustrates why children of color are far more likely to be reported to the child protection system than white children.

"This is not an anomaly," she said. "One of the reasons this is a problem is that African-Americans are more likely to spank their kids. And if child protection doesn't want to see kids spanked, they're going to get swept up in the system."

Racial disparities in Minnesota's child protection system have persisted for years, and extend beyond the mere reporting of abuse.

Once maltreatment is reported, child protection workers are far more likely to launch formal investigations of black families, which can result in the children being removed. By contrast, when the abuse involves white families, child protection workers are more likely to put the families on a track known as "family assessment," which is designed to keep families together by offering parents social services.

White families are twice as likely to be placed on the family assessment track as black families, state data show.