A North Texas man is in jail, accused of the brutal murder of an 82-year-old Addison woman.
The murder happened July 1 at the Communities of Bent Tree apartments on Westgrove Drive near the Dallas North Tollway in Addison.
Detectives working the case gathered evidence and were ready to arrest a suspect, only to find out he was already in jail for allegedly attacking another woman days after the murder.
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Walter Portillo, 30, is in Dallas County Jail on $700,000 bond, accused of two crimes, including murder.
The second crime was an attack on a Garland woman.
The second woman survived and agreed to speak with NBC 5 without showing her face.
She said Portillo, a stranger, was sitting outside her workplace in Garland on July 9.
She asked him to leave, but he refused. She said she told him she was going to call police.
According to the woman, Portillo changed his shirt, waited for her to walk out and attacked her.
He is accused of hitting and kicking her, breaking her wrist and tailbone.
"He's evil," the woman said. "When he looked at me the anger in his face is just it's a vision you don't forget."
Incredibly, the woman credited a 17-year-old who was working with her for saving her life.
The victim said she first told the girl to run when the attack began.
The girl reportedly began to run, but turned back around when she witnessed the beating and began to scream until he stopped.
Garland police arrested Portillo a day later.
"Great police work in catching him to begin with," the woman said.
Eight days before the brutal beating, Joan Mulcahy was murdered outside her apartment unit in Addison.
"She was a real outgoing person. Tremendous. She just enjoyed people," said Mulcahy's cousin Frank Kluge. "I would suspect that on July 1, she was just outside greeting and meeting people. Talking to folks and then this happens."
The 82-year-old longtime teacher and tutor was in her wheelchair at the time of her murder.
Police said her throat had been slashed.
Detectives said surveillance video and witnesses, including a woman who said she believed Portillo followed her to her car shortly after the murder, led police to Portillo in jail.
Addison police said Portillo eventually confessed to the murder and even walked them around the crime scene.
Portillo reportedly told police Mulcahy waved at him and that he killed her because if he saw someone suffering or disabled "he would help them out by killing them" to put them out of their "misery."
"That's the sign of a sick, depraved person who has stooped to about as low as you can get to take another life," Kluge said. "One of the Ten Commandments says don't murder, and yet he did. And he thought nothing of it. He thought this is my duty to do this. No it's not."
Portillo came to the U.S. from his native El Salvador in 2013. Police took a DNA sample during their interrogation.
It was unknown Wednesday if police believe Portillo may be connected to any other crimes.
"I find comfort in the fact that him being caught after what he did to me that it will bring her [Mulcahy] family some peace," the attack survivor said. "[The justice system] needs to take him seriously. He hurt her, killed her. He hurt me and he needs to be prosecuted and he needs to have the full extent of our laws."
Portillo refused an interview from jail.
His court appointed attorney did not return NBC 5's call for comment Wednesday.