A 37-year-old man has been charged with fatally beating one of his infant twins in the family's home in Hudson, Wis.

Paul W. Marshall was charged Tuesday in St. Croix County Circuit Court with first-degree reckless homicide and two counts of child abuse in the Feb. 7 death of the 7-week-old infant and the injuring of the second twin.

Marshall was arrested Tuesday and remained jailed in lieu of $100,000 bail. A court appearance was scheduled for March 1.

The Ramsey County Medical Examiner's Office found five broken ribs in the boy that were in the healing process and skull fractures that had yet to start healing.

The fractures "would result from a significant blow," the criminal complaint read, citing the autopsy's findings. "An accidental fall from being held would not cause the injuries [the boy] suffered."

In response to the allegations in the complaint, defense attorney Aaron Nelson said Wednesday night that "it is unfortunate that all too often, when a child has an injury for which the cause is unknown, rather than conduct a full and fair investigation, those with power jump to an unsupported conclusion."

Nelson explained that Marshall and his wife contacted the boy's doctor a week before the death about "unusual spots on their son's face and swelling around his eyes. The doctor told them to monitor his condition, but did not tell them to bring their son in for medical care. Tragically, several days later on the evening of February 4th, their son stopped breathing and [later] died."

Marshall's attorney pledged that "we plan to conduct a full and complete investigation ... and eventually [show] a fair and impartial jury that the government is wrong: Mr. Marshall is innocent."

According to the charges:

Police were sent to the Marshall home on the night of Feb. 4 about a baby not breathing. Officers arrived to find paramedics tending to the boy. The baby resumed breathing and was taken to Children's Hospital in St. Paul. He was declared dead three days later.

A doctor at the hospital said "he had some concerns" about the child, specifically about a skull fracture that had gone undiagnosed and bleeding on the brain, the complaint read. The doctor said he suspected the parents, who were at the hospital, were not telling the truth about their boy's injuries.

Another doctor told the mother, Sarah Marshall, that her other twin, a daughter, had a skull fracture but no bleeding on the brain, broken ribs that were healing and leg fractures.

The mother told police that on Feb. 4 her husband took the twin boy downstairs to the cool basement to calm him down. She said he was coming back up the stairs when he told her that the boy had spit up, gone limp and was not breathing.

She described her husband a wonderful father who has no temper and doesn't strike the twins or their 21⁄2 -year-old daughter.

Questioned by police at the hospital, Paul Marshall said the boy had grown fussier in recent weeks. Like Sarah Marshall, he said the boy spit up and went limp while with him in the basement. He denied that he or his wife would ever intentionally hurt their children.

A family friend told police that she has seen Paul Marshall be rough with the babies on several occasions, but she said she just viewed him being "just a man," the complaint read.

The friend said she was "pretty sure he is the one that has done all of this, [and] she thinks these injuries would have been accidental out of frustration," the complaint continued.