SAN CARLOS (CBS SF) – A father whose four-month old son was hospitalized with life-threatening injuries was arrested Tuesday for child cruelty.

The San Mateo County Sheriff’s Office said the child was admitted to Kaiser Permanente Hospital in Redwood City earlier this year. Because of the severity of the injuries, the baby was transferred to UCSF Benioff Children’s Hospital in Oakland, where he was place in intensive care.

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After an extensive investigation, sheriff’s detectives determined that the baby’s father, 33-year-old Carl Walstra, caused his injuries, according to the sheriff’s office.

Detectives arrested Walstra Tuesday on the 100 block of Leslie Dr. in San Carlos after obtaining a $100,000 arrest warrant.

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Walstra was charged with cruelty to a child causing great bodily injury.

The sheriff’s office believes the incident was an isolated case and no other children were harmed.

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Anyone with information about the case was asked to contact Detective Jerri Cosens 650-363-4367 or email her at