KANSAS CITY, Mo. >> Relatives of a 7-year-old boy who suffered horrific abuse before being killed by his stepmother and father and fed to pigs have filed a lawsuit alleging social service workers in Kansas and Missouri knew the boy was being tortured and could have prevented his death.

The maternal grandmother, biological mother and oldest sister of Adrian Jones claim in a lawsuit filed this week that social workers didn’t permanently remove the boy from his home despite documenting repeated calls and reports of abuse over several years. The lawsuit seeks $25 million in punitive damages.

Adrian’s remains were found in a pigsty outside the family’s Kansas City, Kansas, home in November 2015. His father, Michael Jones, and stepmother, Heather Jones, are both serving life in prison without parole for at least 25 years for his death.

The lawsuit, filed in both Jackson County, Missouri, and Wyandotte County, Kansas, said the boy’s death was “an entirely avoidable child-homicide.” It claims social workers “meticulously investigated and carefully documented the abuse” and generated stacks of reports chronicling the abuse.

“But their idea of intervention was limited, almost exclusively, to having A.J.’s father and stepmother sign a piece of paper agreeing to stop torturing the child — the legal equivalent of a ‘pinky swear,’” the lawsuit says. “As it turned out, that signed paper might as well have been A.J.’s death warrant.”

During the Jones’ separate trials, prosecutors said the boy essentially starved to death. Surveillance videos from the home showed his deterioration as he was kept naked in a shower stall, forced to sleep outside and sometimes shocked with a stun gun.

Named in the lawsuit are the state of Kansas, the Department of Children and Families and its director, Phyllis Gilmore. Named in Missouri are 10 employees of the Department of Social Services, as well as the Family Guidance Center of St. Joseph, a Kansas City residential children’s home and employees of both organizations.

The lawsuit says the child service agencies “could have stepped in and rescued A.J. at any point during the child’s lengthy, unimaginable ordeal — that was their job, after all. But instead of intervening, they chose to act like disinterested bystanders.”

Records from Missouri detail several visits to the family and show Adrian told a social worker and police officer that he was being abused. And 2,000 pages of documents released earlier by Kansas detailed contacts with the family going back to 2011. The lawsuit also indicates the boy was sent to therapists and other mental health institutions but was always returned to his father and stepmother.

Rebecca Woelfel, a spokeswoman for the Missouri Department of Social Services, said the agency doesn’t comment on pending litigation.

Spokeswoman Theresa Freed said the Kansas DCF hadn’t been served with the lawsuit and referred to comments Gilmore made earlier this year. Gilmore said tracking the family was difficult because they moved frequently between the two states but she insisted the agency shared information with its Missouri counterparts and “thoroughly investigated” each reported incident of abuse.