1:50 p.m. update: Austin police say the attack on a man in South Austin on Sunday night may have been in retaliation for threats the victim made against a woman, her family and children days before his death, according to an arrest affidavit filed on Thursday.

Fabian Michael Gutierrez

The victim, 23-year-old Fabian Michael Gutierrez, was found badly injured at an apartment complex in the 500 block of East Stassney Lane around 9:30 p.m.

Witnesses told police they’d seen two men chase Gutierrez in a truck through the complex before they got out and assaulted him.

"A witness described seeing the two suspects lying on top of the victim, then getting up and running from the scene," the affidavit said.

Gutierrez was rushed to St. David’s South Austin Medical Center after the attack, but he died from his injuries just before 10 p.m.

READ MORE: Police: 23-year-old identified as victim in Sunday slaying in South Austin

The Travis County medical examiner ruled his death a homicide caused by "sharp force injuries," according to the document.

The affidavit identified one of the suspects as 34-year-old Ricardo Santos, but failed to mention a second.

Santos faces a charge of murder, but he was not in custody at the Travis County Jail on Thursday afternoon, jail records show.

The affidavit said both Gutierrez and Santos were involved in a relationship with a woman with whom Santos had children.

The report said the woman had called police on several occasions between late September and early October to report that Gutierrez had assaulted her.

The affidavit said the woman told police she did not want Gutierrez to get away with what he had done, but wanted to handle it "the right way," rather than the "street way."

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Gutierrez was involved in another altercation with the woman on Oct. 7 and 8 in which she told police he had assaulted her mother, and threatened her and the children she’d had with Santos, the affidavit said.

Police said they believe Santos drove to the victim’s apartment with another man to confront Gutierrez and retaliate.

Investigators tracked Santos down and questioned him about the incident, but he denied having anything to do with it, the report said.

But in the days after the slaying, a witness came forward to tell police that Santos admitted to killing Gutierrez, and another told police he’d seen Santos do it, the affidavit said.

Murder is a first-degree felony punishable by five to 99 years in prison and a fine of up to $10,000.

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