A northwestern Indiana man has been arrested for murder and aggravated assault that resulted in the death of his girlfriend's 5-year-old son.

The boy's bruised body reportedly had fresh bite marks.

Michael Tunstall, 26, told authorities that after a nap, the boy woke up Thursday vomiting and became unconscious after he took the child to a bathtub.

When questioned about the bite marks, the accused said he had played a "bite game" with the boy earlier in the day in order for him to calm down. He added that he had not noticed any bruising on the child's body.

The accused from Homewood, Illinois is in the custody of Lake County Sheriff's Police for the death of the boy, who he was watching at his girlfriend's sister's Schererville home on Thursday.

Records said that Tunstall told the police he and his girlfriend and her children had gone to an open house and a fast food place prior to arriving at his girlfriend's sister's home and putting the younger children down for a nap.

The child woke up after a couple of hours of vomiting, so he carried the boy to the bathtub and, after the boy became unconscious, splashed water on him and notified his girlfriend's sister, who was in the house, as indicated in the probable cause affidavit.

According to the mother, upon going to the bathroom, she witnessed that the child's lips and fingertips were blue then performed CPR. She said she did not see or hear anything before seeing the boy in the bathroom.

But the police said that the 5-year-old died of blunt force trauma that resulted in a ruptured left lung and multiple head injuries caused by several heavy strikes to his body.

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An officer who noticed the bite marks and bruises went to Franciscan Health in Dyer where the deceased body was held.

Court records indicated most of the injuries were experienced around an hour leading to the boy's death.

Further examination revealed the kid's mother had not been home Thursday evening when it transpired.

The woman was working and left at about 5:45 PM at the point when she received a call from home.

The suspect was arrested on Friday afternoon and is being held without bond.

"In my 27 years in law enforcement, I have seen many types of tragedy," according to Lake County Sheriff Oscar Martinez Jr. "But as a police officer, the death of a child is always particularly difficult to accept."

The autopsy indicated that the boy's ruptured lung and other serious injuries inflicted on the boy.

The investigation into the occurrence is ongoing.

In a similar case in Michigan in March, a man was jailed for murder for the death of his girlfriend's infant son.

Police responded after receiving a call from the eight-month-old baby's mother indicating that she found the child lying unconscious in his crib.

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