A Minnesota couple has been accused of abusing one of their two conjoined twins who underwent separation surgery last fall at the Mayo Clinic.

Valerie J. James, 20, and Robert L. Heck III, 27, of Mankato were charged with one count each of felony first-degree assault and aiding and abetting the alleged crime on the 4-month-old, said police Lt. Dan Muyres.

Rochester, Minn., police were scheduled to hold a news conference at 10 a.m. Thursday.

Reached at home Wednesday, Heck denied the allegations but said he would not comment further until he spoke with his attorney.

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James gave birth to the boys — named Jacob and Jordan — in November. Joined face-to-face at the abdomen, they immediately underwent successful separation surgery.

It wasn't immediately clear which child was injured. One of the boys had remained in the hospital after the other boy was released Jan. 3 to his parents, who had been staying at a Ronald McDonald House in Rochester.

Police wouldn't identify the victim, and Mayo officials said privacy restrictions kept them from identifying the child discharged last month.

Blue Earth County has filed petitions against James and Heck in an effort to end their parental rights for the twins and an older daughter of the couple.

According to a criminal complaint, that boy was returned to Mayo Eugenio Litta Children's Hospital Jan. 11 because of some swelling.

Doctors found eight fractures of the boy's legs and 16 rib fractures. The complaint said some injuries appeared to have begun healing, while others were newer.

Doctors did a test to see if the boy had a genetic disorder that could cause his bones to be more susceptible to breaking, but the test came back negative, according to the criminal complaint. Muyres said a doctor told police it would take a large amount of force to inflict the injuries because of the flexibility of infants' limbs.

The complaint said a former girlfriend had obtained an order of protection against Heck in 2004 after she accused him of hurting her three children. The ex-girlfriend said her 3-year-old reported being struck by Heck; that her 18-month-old son suffered a broken leg and head bruises while in his care; and that her 3-month-old had burns on her fingers that doctors attributed to cigarettes.

Muyres said he had no other details on the order of protection.

An April 12 court date was set in the case. Both children were in supervised care away from the parents.

It wasn't immediately known whether the older child was still with the couple.

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