Besides the victim's and the chief witness's identifying Feit — besides witnesses contradicting his story — the most damning evidence was Feit's mangled left pinkie finger, which several fellow priests and church workers noticed in the days after March 23.
In Feit's initial statement to police, he explained that his finger had been injured in a church mimeograph machine the day before Guerra was attacked.
"In trying to make the stencil ink better, the little finger of my left hand caught between the revolving drum and the frame breaking the skin and causing a severe bruise."
Feit wrote that on Tuesday night, the day before Guerra was attacked, he asked a Father Houlahan for some rubbing alcohol to soak his finger.
Feit wrote that he also went to the secretary at the Edinburg church on the morning of March 23 asking for a bandage for the injury. Feit said, "She asked me how I hurt my finger, and I said I hurt it in the mimeograph machine."
Father Houlahan, in his statement, said that Feit came to him later in the week regarding his wounded finger.
And a secretary at the church in Edinburg was adamant in her statement that Feit came the morning after the Guerra attack asking for a bandage. And she was vocal in her suspicion that her mimeograph machine could not have done the damage to Feit's finger.
That secretary, Cleotilde "Tilly" Sanchez, still lives in the McAllen area. And she says she still vividly remembers the events of March and April 1960.
She remembers walking in as the church's other secretary, Leonila Sanchez, was putting iodine on Feit's finger.
"I didn't just ask Feit what happened to his finger," she tells New Times. "I asked, 'Who bit your finger?' It had teeth marks on it. It was as clear as day.
"Feit said, 'It isn't a bite.' I said, 'Well, it sure looks like a bite. You can see the mouth shape on it.'"
Sanchez says she had come to know Feit well during that spring. Feit was often over visiting Moran. Feit, she says, was always calling the church asking for Moran or for help with some issue.
"Pretty early on, [Feit] wouldn't have to say his name when he called," she says. "His voice was that distinctive, and he was calling that much."
In late April or early May of that year, after Irene Garza's body was found, after Sanchez had made her statements to police, a call came into the church that chills her to this day.
"It was a Friday," she says. "The phone rings, I pick it up and a man says, 'You're next, Tilly.' I said, 'What?' And he says, 'You're next!'
"It was Feit," she maintains. "I knew his voice immediately. Father Moran walks in, and I tell him Father Feit just called and said, 'You're next,' and Father Moran just says, 'Oh, Tilly, it couldn't be Father Feit.' By that point I was just scared to death."
She quit her secretary job soon after.
Investigators were confident they had an ironclad case against John Feit in the Garza killing.
But they held off pushing for charges. They wanted to have something to offer Feit.
The deal they came up with was this: If Feit would confess to Irene Garza's murder, they wouldn't bring a charge in the Guerra case. He wouldn't have to face two trials.
In reality, it wasn't a very big carrot. Avoid an assault-related charge by confessing to rape and murder?
Feit refused to confess that he killed Irene Garza. In the summer of 1960, Feit was charged with the attempted sexual assault of Maria America Guerra.
Even without a confession, though, investigators felt confident they had more than enough evidence to charge John Feit with the murder of Irene Garza.
That never happened.
On May 3, 1960, two weeks after Irene Garza disappeared, police asked John Feit to give a sworn statement of his whereabouts on Easter weekend.
At 7 p.m. on the Saturday before Easter, he told authorities, he and Father O'Brien were leaving the rectory heading for the church when the phone rang.
Feit said he returned to the rectory to answer it.
He said a woman was on the line asking to see Father Junius, who was already taking confessions in the church.
Feit said he told the woman that Father Junius would be busy until 10:30 p.m., but that he could talk to her if she hurried down to the church.