A 59-year-old man who repeatedly sexually assaulted a three-year-old boy has been sent to prison for over a century.

Mario Hernandez, from Upland, California, was convicted to 106 years behind bars.

The abuse was carried out over a span of seven years from when the boy was three years old, according to the San Bernardino deputy district attorney Karen Schmauss.

Hernandez reportedly often withdrew food from the boy to bribe him to perform sexual acts, added Ms Schmauss, and he would tell the child: "You owe me."

"He would also refuse to sign the boy's school planner if he did not cooperate," Ms Schmauss said in a statement.

"As the victim grew older, Hernandez threatened harm to the boy and his brother if they told anyone."

When he was 10 years old, the boy told his school friends what was happening.

Hernandez was charged with three counts of sodomy with a child of 10 years or younger, one count of oral copulation with a child aged 10 or younger, and one count of continuous sexual abuse of a child. He was given the maximum sentence on 3 June.

Judge Stanford Reichert added: "The crimes showed a high degree of cruelty, viciousness and callousness."

Ms Schmauss said Hernandez would never hurt a child again.