MARTINEZ -- After hearing impassioned arguments from both attorneys, a Contra Costa judge on Monday sentenced a Concord man whose pit bulls fatally mauled his step-grandson to one year in county jail and three years' probation.

Steven Hayashi, 56, convicted of involuntary manslaughter in April, could have been sent to prison for 10 years.

"I don't believe state prison is warranted," said Judge John W. Kennedy, noting that Hayashi had never been arrested before July 22, 2010, when three of his five pit bulls attacked Jacob Bisbee, 2.

Prosecutor Mary Knox implored Kennedy to sentence Hayashi to the maximum penalty — 10 years in prison.

Steven Hayashi enters the Bray Courthouse in Martinez, where he was on trial for the 2010 fatal dog mauling of his 2-year-old grandson Jacob Bisbee, in
Steven Hayashi enters the Bray Courthouse in Martinez, where he was on trial for the 2010 fatal dog mauling of his 2-year-old grandson Jacob Bisbee, in Martinez, Calif., on Wednesday, Aug. 21, 2013. (Dan Rosenstrauch/Bay Area News Group)

"There were so many warning signs," Knox said, citing a family Chihuahua that was "basically eviscerated by the pit bulls," a cockatiel which was "ripped to shreds" and an incident two weeks before the fatal attack when Jacob wandered out of the house and was about to step onto busy Concord Boulevard when a passerby intervened. She also reminded Kennedy that Hayashi had been asked several times by family members to get rid of the dogs, and that although Hayashi cared for Jacob and his brother Jeremy, there were "literally no child safety locks anywhere in that house."

The prosecutor enumerated the gruesome wounds inflicted on the boy, including more than 100 bite marks.

"When does this stop being a case about probation and when does this become a case of punishment for selfish choices ... for a malignant heart?" Knox asked.

Defense attorney David Cohen argued just as forcefully for leniency on behalf of his client.

"The experts in this case were in agreement, that only when dogs attack human beings is there notice there might be a problem," Cohen said. "There's no red flag just because of some kind of barking at the fence. (Hayashi) had no knowledge these things were going to happen."

Before the attorneys had their say, Kennedy heard from Jacob's mother, who pleaded with Kennedy to show Hayashi lenience. "I really believe that Jacob's death was an accident in which we all share some of the blame," the woman said, crying as she read a prepared statement. "It would be a disservice to Jacob's memory if Steven were to go to prison. This is a man who cared for my children."

Hayashi, who was laid off in 2009 and was attempting to find work at the time of the incident, cared for the young sons of his stepson Michael Bisbee. On July 22, 2010, Hayashi left the house to play tennis, leaving the boys unsupervised. Cohen argued at trial that Hayashi believed his wife was awake when he left the house; in fact, she was asleep. Jacob was attacked when he entered the unlocked garage where the dogs were kept.

Hayashi also read a statement Monday morning in which he recalled being initially resentful about having to care for the boys but grew to love being around them.

"They were my grandchildren," he said. "No one can possibly comprehend the pain Jacob's death has caused me. I truly feel terrible about the pain I have caused."

Hayashi added that the incident and its aftermath have "left us in financial ruin and emotional turmoil."

Kennedy, who denied Cohen's motion for a new trial Monday morning, agreed to allow Hayashi to remain free on bail pending appeal of the decision. As part of probation, Kennedy ordered that Hayashi not own or possess dogs or any other dangerous animals at his residence. He also ordered Hayashi to complete a parenting class.

Contact Gary Peterson at 925-952-5053. Follow him at Twitter.com/garyscribe.