RIVERVIEW, Fla. -

Two pit bulls that mauled a 4-year-old Tampa Bay-area boy have been euthanized.

Logan Shepard's uncle owned the dogs. The boy was visiting his uncle's Riverview home Saturday when he was killed in the yard.

Police said Billy Frederick Sr. put the dogs in cages before the boy arrived. Logan's father said the dogs were later released into the yard.

No charges have been filed. Police have said Logan was left alone while the adults talked in another room, but Frederick's wife claimed Logan was watching television with a teenage cousin.

Police said the adults heard screams and discovered the dogs standing over Logan in the yard.

Hillsborough County authorities said Frederick voluntarily surrendered the dogs, which were euthanized.