Investigators believe a 22-year-old woman who was found dead in a Bronx park Sunday morning was fatally stabbed by her ex-boyfriend. Police received a 911 call from Khiry Borden, 25, shortly before 6 a.m., reporting the discovery of his dead ex-girlfriend, Jasmine Gonzalez, in Bronx River Park. Borden apparently claimed he was walking a dog belonging to Gonzalez's family when he stumbled upon her body.

Borden, who is the father of Gonzalez's 2-year-old son, had reportedly stashed a bookbag behind a curtain in the living room of the Gonzalez family home on East 225th Street. Police arrested Borden after finding "bloodstained jeans and a towel, along with an empty package for kitchen knives" in the bag, according to the victim's sister, Jayselle Gonzalez.

Borden has been charged with murder, manslaughter and weapons possession. The NYPD reports his address as 1620 Saint Johns Place in Brooklyn, the location of the St. John’s Place Family Center, which provides temporary housing for the unemployed. Police sources tell the Daily News he has seven prior arrests, for crimes including slapping a pregnant woman and robbing a teenage girl.

"He used to cheat on her, so then she finally moved on, found someone new, and he was jealous of that," Jasmine's sister Jayselle Gonzalez tells ABC 7. But she said the two spent July 4th together, and went out for a walk late that night. "They didn't want to fight in front of the baby, so they took it outside, and I guess as they walked to the park, it got physical from there," Jayselle says. The News also pieced together these details about the murder:

“He came back here while everybody was sleeping. He changed his clothes to a new set of clothes he had in his bag,” Gonzalez’s sister, Jayselle, said.

After hiding the bag, the ex-beau woke up the victim’s mother, the grieving sister said.

“He asked my mom for the dog chain. So my mom gave it to him,” she said. “So, I guess when he took the dog down there (to the park), he made it seem like he was walking the dog and found his baby’s mom dead.”

Gonzalez was found dead with multiple stab wounds to the torso.

“They were recently fighting,” one family friend tells the Post. “They fought over their child, the care of their child, all the time.”

“He was the quiet type — too quiet; it was almost suspicious.” Barbara Lopez, Gonzalez’s aunt, tells the Times. “I have no doubt it was him. I never trusted that boy. Now look what happened.”