Professional boxer Felix Verdejo turned himself in to the FBI on Sunday night to face federal charges after his lover's body was found in a lagoon near the capital San Juan.

The US Attorney's Office named the charges against the 27-year-old Verdejo as kidnapping and carjacking resulting in death, and intentionally killing an unborn child.

The body of Keishla Rodriguez was discovered on Saturday, several days after she had been reported missing.

The FBI said that Verdejo, who is married and has a daughter, assaulted his lover and injected her with an unknown substance before binding her hands and feet to a heavy object and throwing her in the river, at which point he began shooting at her body from the bridge.

Hundreds of people gathered by the lagoon on Sunday to demand justice for Rodriguez and for other female victims of domestic violence.

What relationship did Rodriguez and Verdejo have?

Rodriguez's mother Keila Ortiz told reporters that he daughter had called her on Thursday before disappearing and said that Verdejo was on his way over to check the result of a pregnancy test.

Ortiz warned her daughter to be careful because Verdejo "had already threatened her" not to have the baby, fearing for his family and career.

Rodriguez and Verdejo knew each other in middle school and had kept in touch, the victim's parents said. She was reported missing after not showing up for work on Thursday.

Verdejo was questioned by police in relation to Rodriguez's disappearance on Friday, but the boxer refused to cooperate at the time.

How did people respond to the violent crime?

Puerto Rico's Governor Pedro Pierluisi reiterated his "commitment to the fight against gender-based violence" on Sunday, while at the same time announcing a reduction in funding for fighting gender-based violence by the Financial Oversight and Management Board for Puerto Rico.

The protesters who came out on Sunday to demand an end to violence against women met under the call for a "national cry that will be heard in all corners. For those who are no longer with us and for those who will come."

The murder of Rodriguez brought further outrage after another woman was burned to death after filing a domestic violence complaint that was dismissed by a judge.

Verdejo first gained prominence after reaching the quarter-finals of the London Olympics in 2012, turning professional that same year.

ab/msh (AP, EFE)