GRAND RAPIDS, MI – A prosecutor said the trial for a man accused of killing his infant daughter during an oral rape took a toll on everyone - family, investigators, attorneys and the jurors who were subjected to disturbing testimony and photos before convicting Steven Deuman Jr. of first-degree murder.

“This was a very difficult case for anyone to have to hear,” Assistant U.S. Attorney Phil Green said Wednesday.

“This is about as heinous as it gets. That’s a tragic reality here. He did do it. A beautiful 15-week-old baby girl lost her life, lost her future, because of his need for sexual gratification.”

Deuman, of Suttons Bay near Traverse City, was convicted of first-degree murder and aggravated sexual assault of his 15-week-old daughter, Evelynne Deuman.

He shook his head back and forth as U.S. District Judge Gordon Quist read the verdict. Jurors deliberated about an hour. A sentencing date was not set, but Deuman faces a mandatory sentence of life in prison.

He maintained that he put his daughter on his bed while he stepped outside for a cigarette. He returned to find her not breathing on the floor and with a discarded condom in her mouth, the defense said.

Green said that Natasha Maitland, the baby's mother who also has a son with Deuman, too, proved extremely important in the investigation. She testified on behalf of the prosecution.

“I could not be more impressed with Natasha Maitland’s courage through this whole process," Green said. "She is a remarkable young woman. It’s my fervent hope she can put her life back together. She was forced to endure (a loss) no one should ever have to endure.”

When the judge read the verdict, Maitland wept and hugged those near her.

Later, someone whispered, “Justice was served.”

They declined to comment as they left the courthouse.

Maitland was at work on Aug. 12, 2010, when her daughter died.

Green told jurors that Deuman killed the girl during the oral rape, and then he considered scenarios throughout the evening to suggest she died of an accidental cause. He didn’t call 911, but told Maitland on the telephone that their daughter wasn’t breathing.

By the time he talked to Maitland, the girl had likely been dead for some time, Green told jurors.

“He’s got to come up with a potential explanation for what they might find in her mouth,” he said. “The ultimate question is, how did that condom get in her mouth?”

Green said Deuman’s version of events didn’t make sense.

“This was no accident. She couldn’t roll over, much less crawl. She certainly wasn’t capable of overcoming the obstacles on her bed, the pillows, to end up on the floor. Even if (she did), how is she going to suck that condom up?”

Finally, Green told jurors: “It’s hard to imagine anything more objectionable than the oral rape of a 15-week-old baby.”

Jurors also heard from witnesses who, as children, claimed they also were sexually abused by Deuman.

Defense attorney Richard Stroba said his client was a "proud father" who wouldn't harm his own children. He insisted the death was an accident.

He said that tragedy wasn’t necessarily a surprise given that 10 people, along with a dog and cat, shared a double-wide mobile home in Leelanau County.

“The reality is, that room, that house, was an accident waiting to happen,” Stroba said.

He said prosecutors unfairly portrayed his client as an “unbridled sex fiend.”

The case was handled in federal court because the killing occurred on an American Indian reservation in Northern Michigan, land held in trust by the federal government for the Grand Traverse Band of Ottawa and Chippewa Indians.

E-mail John Agar: jagar@mlive.com and follow him on Twitter at twitter.com/grpressagar