CALDWELL -- A Caldwell man is facing felony charges after police say he badly injured his girlfriend's young children last year.

The investigation began in August 2015 after 25-year-old Luke Ray Baker brought his girlfriend's two-year-old daughter into West Valley Medical Center with a severely infected wound on her left arm.

Baker and the child's mother told doctors she had been bitten by a spider, but a doctor with St. Luke's CARES who examined the girl told police the injury appeared to be a burn, possibly from a cigarette.

Baker and the mother - who was not identified in court documents - said the injury had happened three days before the child was brought to the hospital. Baker said they had tried treating the wound with baking soda, but by the second day, "it was like to the point we're going to the hospital.. as it's eating her alive," according to police documents.

Baker and the child's mother waited another day before seeking medical help for the two-year-old, they said.

Doctors say the depth of the wound proved it had happened earlier than a few days before. The injury was so badly infected the girl was transferred to St. Luke's in Boise for surgery.

Medical personnel who examined the child also noted a cut or gouge over her eye, bruises on her forehead and face, and a burn on her left leg that matched the size and shape of a cigarette lighter. The girl also showed signs of dehydration and malnutrition, according to court records.

While the two-year-old was being treated, Baker also brought the girl's one-year-old brother into the hospital, telling medical personnel he had discovered a severe injury to the baby's genitals while changing his diaper.

According to court documents, Baker said he had opened the infant's diaper to see blood and "screamed bloody murder" when he saw the injury.

Staff at West Valley Medical Center told police the baby had a badly swollen penis and bruises on his groin area, as well as a black eye. Although the baby's mother said the boy did not have the injuries to his groin when she changed him earlier in the evening, doctors say the bruising was not consistent with trauma that was just a few hours old.

Doctors told police that the children's injuries were not accidental.

Baker told officers the girl's bruises were from falling out of a chair and her brother throwing toys at her. He also told police he and his girlfriend were the children's sole caretakers.

After an officer confronted the suspect about the lighter-shaped burn on the child's leg, Baker said he was getting an attorney and stopped talking to investigators.

According to court documents, the toddlers' mother confided to investigators that she was afraid of Baker. She also said that Baker had previously taken her children into their room and refused to let her in once they started crying.

Prosecutor Erica Kallin said the children were immediately removed from the care of Baker and their mother. Theyare now living with their biological father.

Kallin said the prosecutor's office gathered medical assessments and fully investigated the case before issuing a warrant for Baker Nov. 23. He was arrested Tuesday morning and booked into the Canyon County Jail.

The suspect is charged with three felony counts of injury to child, and a possible sentencing enhancement for infliction of great bodily injury.

No charges have been filed against the toddlers' mother as of Wednesday.

Baker is held on a $50,000 bond, and is due to appear in court Dec. 13. Felony injury to a child is punishable by up to 10 years in prison, and the sentencing enhancement could extend any sentence by up to 20 years.

If you suspect a child is being abused or neglected in the Treasure Valley, call the Idaho Department of Health and Welfare's abuse hotline 208-334-KIDS (5437.)