A jury deliberated about four hours Friday before convicting a Lawrence man of murdering his 5-month-old daughter.

Jurors found Jay D. Decker, 27, guilty of first-degree murder in the Oct. 14, 2005, death of Risha Lafferty, who died with a skull fracture and signs of being shaken. He will be sentenced Jan. 3 and faces 20 years to life in prison.

“It’s mind-boggling to have cases like this where you’ve got a death of a child for no apparent reason,” Dist. Atty. Charles Branson said after the verdict was announced.

In her closing argument, assistant Dist. Atty. Amy McGowan flashed a series of photos of Risha’s bruised head and neck.

“Risha is here. She speaks to you through these injuries that she had,” McGowan told jurors. “Her voice is here in court.”

Defense attorney Tom Bartee said in a closing argument that the series of injuries the baby suffered in the weeks leading up to her death – all while in Decker’s care – could have been accidental. He argued that the baby’s mother, Brandi Mae Hendrickson, had been abusive in the past and that the timeline of events suggested she could have abused the baby in the hours before she was found dead.

“Jay Decker did not do this. Brandi Hendrickson did. He’s not guilty,” Bartee said.

Douglas County Sheriff's Sgt. Ken Fangohr, left, leads Jay D. Decker out of the courtroom Friday after jurors found Decker guilty of first-degree murder in the abuse death of his 5-month-old daughter, Risha Lafferty.

Hendrickson was charged with felony child endangerment for failing to report some of Risha’s injuries, but she agreed to plead to a misdemeanor in exchange for testimony against Decker. She is due in court next week.

Risha had more than 30 bruises on her body when she was found dead. Decker told detectives that in the days leading up to her death, she had a series of accidents while in his care – including one incident in which he said he fell into the wall while holding her.

A cut-out piece of drywall showing a circular dent was among the physical evidence presented in the case.

“The disturbing thing about that dent in the wall is it’s the size and shape of an infant’s head,” McGowan told jurors.

Decker showed little reaction when the verdict came in, but his sister and mother sobbed. They previously had said they supported Decker and believed in his innocence.

6News reporter/anchor Janet Reid contributed to this report.