A 36-year-old U.S. Army veteran was convicted on July 20 of fatally beating a 68-year-old neighbor during an attempted rape in Garden Grove nearly six years ago.

Michael Aon Varela was convicted of murder with a special circumstance allegation of murder during an attempted rape.

It was Mr. Varela’s second trial. A previous jury deadlocked 7–5 for guilt, leading to a mistrial being declared on Oct. 26.

Mr. Varela, who is scheduled to be sentenced on Aug. 4, faces life in prison without the possibility of parole.

Jurors, who deliberated for about a day, had earlier sent a note asking if they could find the defendant guilty of second-degree murder with the special circumstance allegation. When they were told that was not legally possible, they found him guilty of first-degree murder and found the allegation true.

Mr. Varela was convicted for the killing of Dzung Thi Nguyen in September 2017.

In last year’s trial, Dan Feldman, the previous prosecutor in the case, said Mr. Varela went to a local bar to watch a mixed martial arts fight the night of Sept. 9, 2017, and made his way home about 5 a.m.

The new prosecutor in the case, Casey Cunningham, said it was just after 5 a.m. Sept. 10, 2017, when the defendant’s father, Carlos Varela, came out of his house to see his son shirtless with his pants unbuttoned and blood smeared across his chest as he stood over a partially unclothed woman virtually beaten to death.

Mr. Varela, who was 30 at the time, lived with his father and his father’s girlfriend, Allison Hogan. Mr. Varela, who had served in the U.S. Army for two years, was taking classes at a community college at the time.

Mr. Varela had been sober for about four years before that night, Mr. Cunningham said.

Mrs. Nguyen had her shirt pulled up, exposing her chest, and was nude from the waist down, Mr. Cunningham said. Her nose and orbital socket were broken along with the hyoid bone.

Mrs. Nguyen’s brain was bleeding so badly that surgeons had to remove a portion of her skull, but she died at a hospital on Sept. 21, 2017.

According to Mr. Cunningham, when Carlos Varela asked his son what happened his son shouted, “What? You think I did this?”

The prosecutor argued that if someone else had raped her before the defendant showed up, there would be DNA from someone else on her.

“He beat her. He strangled and killed her,” Mr. Cunningham said. “She died because of what he did to her.”

Over the years, Mr. Varela has “admitted a bunch of lies ... and told more lies,” Mr. Cunningham said.

He claimed he “stumbled upon this poor victim,” Mr. Cunningham said.

When his father sees him with the victim, “He’s got his fly undone—that speaks volumes,” Mr. Cunningham said.

Investigators found her DNA on his penis, and his sperm was found on her breasts, Mr. Cunningham argued.

“The defendant’s DNA is on her underwear,” Mr. Cunningham said.

The Defense

Mr. Varela’s attorney, Arlene Speiser of the Orange County Public Defender’s Office, said her client was “shouting his innocence” to his father and acted like anyone wrongfully accused would.

“Even the calmest person would be shouting and professing their innocence,” Ms. Speiser said. “He was the convenient one thrown under the bus when all he was trying to do was to help someone.”

Ms. Speiser argued that police failed to follow up on other people seen near the crime scene at the time of the attack. A bag of trash found nearby contained two used condoms, which did not contain a match to Mr. Varela, but they were not tested to link to anyone else, Ms. Speiser said.

One potential witness was subpoenaed to come to court and when he failed to show a bench warrant was issued, according to court records. Ms. Speiser said the neighbor she wanted to testify in the case had a criminal history of assault and mayhem.

She accused the lead investigator on the case of withholding evidence and choosing to record some interviews, but not others.

“They admitted they made mistakes in this case,” Ms. Speiser argued.

A neighbor spoke to a “disheveled man” who was seen in the area, but police did not chase down that clue, she argued.

She said the attack was entirely out of character for Mr. Varela, who had no criminal record.

“He was always the kind to jump in and help others,” Ms. Speiser said. “A rapist and killer is not that way and they know it and it does not fit their narrative ... No one believes he was capable of this.”

Ms. Speiser also highlighted how the neighborhood had a lot of transients in the area and more activity than usual in the early morning hours. The victim’s husband had warned her it was dangerous to go out walking in the middle of the night, according to Ms. Speiser.