She brought joy to their lives like only a grandchild can.

Their granddaughter gave birth to the healthy girl in early 2014. A couple of days later the baby came to their house to live with them, their granddaughter and the infant’s father.

The home was filled with the sounds of new life.

“She always had a smile and would giggle and laugh. She would kick her little legs and grasp with her little hands and was a joy to have in our lives,” the Mukilteo couple wrote of their great-granddaughter.

She was growing, eating cereal from a spoon and drinking from a bottle. She loved bath time with bubbles.

The girl will turn 3 in a few months. She doesn’t live with them anymore. She needs around-the-clock specialty care. The couple moved, unable to bear the memories of what happened there.

“She cannot see, talk, eat normal and will never crawl or walk,” they wrote. “She no longer smiles.”

The couple earlier this week faced the man convicted of robbing their great-granddaughter of a healthy life.

The child’s father, Bothell resident Jacob Tusken, wore a jail uniform and shackles.

“I would like to ask Jake what did (his daughter) ever do to him? What did (she) do that was so bad that he did this to her?” the child’s great-grandmother asked.

Superior Court Judge George Appel on Tuesday sentenced Tusken to nine years in prison for the injuries he caused his daughter. Tusken, 22, in September had pleaded guilty to first-degree assault of a child after a long series of negotiations.

“She won’t have any life any parent would hope or pray for their child,” Snohomish County deputy prosecutor Jarett Goodkin said.

That’s her father’s fault, he added.

Goodkin told the judge that a trial would have been a battle of medical experts in a highly contested scientific field. The state’s medical experts would have argued that the girl’s injuries were the result of abusive head trauma, formerly known as “shaken-baby syndrome.”

That was expected to be “vehemently contested by the defense,” Goodkin said.

Bothell police began investigating Tusken in 2014 after being contacted by Child Protective Services. Tusken and the girl’s mother took the 4-month-old baby to the hospital because of seizure activity. A medical team discovered that the girl’s brain was bleeding and suspected child abuse.

Doctors concluded that the infant likely suffered a traumatic injury two to three days before she was brought to the hospital and the symptoms had become worse as her brain swelled. They also found an old brain injury, Bothell detectives wrote.

Her left forearm was slightly deformed. Several of her ribs had been broken, likely a couple of months before she was seen by doctors at Harborview Medical Center in Seattle.

Tusken cared for his daughter while the girl’s teenage mother was attending cosmetology school. He also told detectives that he woke up at night to feed and change the baby.

During their investigation detectives seized the parents’ cellphones. They found photographs of the baby with injuries to her lip, left eye and head. One picture shows that the girl’s head appears abnormally swollen, records show.

There were videos of the baby having seizures. Tusken’s phone also showed that on numerous occasions someone searched online for information about infant seizures, sleep patterns, rib fractures and broken bones. Police discovered the phone was used to search Google for “Can a two month old break or crack their ribs?”

Doctors told detectives that a baby’s ribs are pliable and it would take a considerable amount of force to break them. The doctors also said that a person would likely hear or feel the ribs snap.

Tusken’s online history also showed that someone was doing research on how much babies can remember, police wrote.

Criminal defense attorney Walter Peale told Appel that there was uncertainty about what happened and when, all which would have been explored at trial, but his client wanted to take responsibility and spare his family a trial.

“I can tell you Mr. Tusken is remorseful… He’s not that same person any more,” Peale said.

Tusken read from a letter before Appel handed down the sentence. He told the judge that his daughter is always in this thoughts and he prays for her. He had wanted to succeed as a father.

“It’s been as hard for me as it’s been for everyone else,” he said.

Appel ordered Tusken never to have contact with his daughter.

“You have done a terrible thing,” the judge said. “There’s no way anyone can undo the damage.”

Diana Hefley: 425-339-3463; hefley@heraldnet.com.