A group of men stabbed spring breaker 21-year-old Derek Madrigal of Dallas nine times Saturday, according to the victim's father.
Frank Madrigal said Valley Baptist Medical Center in Harlingen called to inform him that his son's lung was ruptured in the attack on South Padre Island.
Police arrested 33-year-old Michael Rangel of San Antonio.
He's now charged with aggravated assault with a deadly weapon.
A judge gave Rangel a $20,000 bond.
Madrigal said his son was defending a woman who was being assaulted on Coca Cola beach; that's when he was stabbed.
"I was born and raised in the RGV and spent many summers on the Island," said Madrigal in an email. "I cannot believe that this kind of violence exists among our youth."
Madrigal said Derek is a college student in Dallas.
He said he will travel to the Valley Monday.