Struggling through tears, Shannon John said she wanted to know why.

"Why would you do that to a baby? I just don't understand," she said in federal court Tuesday as her former boyfriend, Edgar Lynn Chee, sat and watched before being sentenced to two years in federal prison for the death of 2-year-old Xavier John.

"Why would you tell them you love them and do this?"

Although Chee, 36, was originally charged with murder for the boy's death, federal prosecutors said the medical examiner's report could not definitively show how Chee killed the boy. Chee ended up pleading down to the charge of involuntary manslaughter.

According to charging documents, Shannon John left Chee alone with Xavier at their home on the Navajo reservation to watch him while she went to drop off a friend at work and then run errands. John told authorities she was driving home when she saw Chee driving toward her in his father's truck. "He flagged her down and gave her Xavier. His body was lifeless. John drove Xavier to the Monument Valley Health Center where he was pronounced dead upon arrival," wrote FBI special agent Rachel Boisselle in the charging document.

Chee initially told officers he found the boy sleeping on the sofa with a blanket over his head and that his lips were blue and he was not breathing. Later in a post-Miranda interview in jail, Chee admitted that he killed the boy accidentally by falling on him.

"I just wanted to say that I'm very sorry," Chee said in court. "I know I'll have to live with this for the rest of my life."

Chee admitted to drinking and smoking marijuana that day in August 2007 and that he didn't remember much of what happened.

"Did you lose your temper with the baby? Was that part of it?" asked U.S. District Judge Tena Campbell. Chee admitted in court that he did lose his temper.

Chee's defense attorney, Robin Ljungberg, said his client had no past history of violence against any of his other 11 children.

John said she was left to care for children with no job when Chee was arrested and that she had no money to pay for her son's funeral, nor clothes for the burial.

Given the government's plea agreement, Campbell said she had no choice but to sentence Chee to the statutory maximum of two years in prison without a divergence from the sentencing guidelines. She also ordered Chee to attend anger management treatment while in prison.

John said she wanted justice for losing her son. "It was my son that I lost. I will be the one who will suffer," she said.

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