Navy man confessed to killing wife but later retracted it, court is told

Mary Marx did not say a word when she walked into her Algiers home on May 25, 2011, and found her estranged husband standing in the kitchen, covered in mud and clutching a crossbow. She just looked at him, he later told police, “like she was the devil.”

David Marx allegedly aimed his crossbow, so powerful it can launch an arrow the full length of a football field in one second, and pulled the trigger.

The first arrow severed her spinal cord, paralyzing her instantly. She fell back onto the floor of their son’s bedroom, but she was still alive. So her husband reloaded and fired again, this time at her face.

Marx, then a Navy chief petty officer stationed in Virginia, is on trial this week on a charge of second-degree murder, facing an automatic sentence of life in prison if a jury finds him guilty as charged.

Prosecutors said he was living a double life. He lived with his girlfriend and her son in Virginia, while he financially supported his wife and their 12-year-old son in Louisiana.

“Mary Marx started to become an inconvenient burden,” Assistant District Attorney Payal Patel told the Orleans Parish Criminal District Court jury. “Mary Marx was pretty much dead to David Marx long before he planned her murder.”

David Marx told detectives he’d been plotting to kill her for a month. He allegedly took the time to bargain-shop for his weapons: Police found in his Virginia house a handwritten list pricing crossbows. He drove from Virginia to Pensacola, Fla., with his girlfriend, then left in the middle of the night to catch his wife by surprise the next morning.

“I was thinking about going down there and finishing her off,” he told detectives in a recorded statement. “Because there was no way out. I was so frustrated with her.”

But now Marx says he didn’t do it. His defense attorneys, Frank DeSalvo, Bruce Netterville and Brigid Collins, suggested that investigators had tricked Marx into confessing to the crime.

The killing was investigated by both the New Orleans Police Department and the Naval Criminal Investigative Service.

Marx, now 46, had been a sailor since 1987. He was stationed, for a time, in the New Orleans area, and he and his wife bought their pink shotgun house on Nunez Street in Algiers Point in 2007, according to court records. He moved to Virginia in 2010, met his girlfriend and moved in together with her. He told police his marriage had not been happy for more than a decade.

Mary Marx took care of their son alone. He husband had not visited them for six months.

The boy was diagnosed with Asperger syndome, a form of autism that can cause a child to become withdrawn and isolated. He was bullied at school and devastated when his father moved away, his psychiatrist testified Wednesday. The boy became deeply depressed and told his teacher he was contemplating suicide.

Mary Marx, 51, took him to school each day and picked him up each afternoon. But no one came for the boy on May 25, 2011. His school grew concerned and contacted a neighbor to fetch the child. The house was locked, and the boy ran along the side, peeping through the windows.

The neighbor testified that she heard him scream. He had seen his mother’s body lying in a pool of blood through his bedroom window. The coroner determined she’d been killed hours earlier, at 8 a.m., according to court records.

Detective Barret Morton wrote in his report that the killer had staged a fake burglary: Cabinets and drawers were open, but the contents were still inside. Televisions and laptops were left undisturbed, in plain view. The door was locked and required a key to open it. There was no sign of forced entry.

Morton tried to call David Marx, then stationed in Norfolk, Va., over and over but got no answer. Navy investigators tried to track him down, also to no avail.

David Marx returned the detective’s calls the next day. He said he’d been in Florida and his phone had stopped working. The detective told him his wife was dead.

Marx did not ask how she died and police grew suspicious.

NCIS staked out his home in Virginia and picked him up for questioning. Over the course of a three-hour interrogation, his story changed wildly. At first he said he hadn’t been to New Orleans at all, but investigators told him someone had seen his white SUV there. So he said he’d grown nostalgic for the Crescent City and drove to the city to reminisce. He did not go to his neighborhood, he said. But then detectives told him that two witnesses spotted him wandering near his wife’s house, caked in mud and dirt. So he said that he had, indeed, gone there, but just to take a walk, and never went inside.

He finally confessed to the killing, and described it in detail.

He’d gone there early in the morning, before dawn, and crawled underneath the house with the crossbow. He waited for his wife to leave to take their son to school, then he crawled back out and went inside.

The house was a wreck, he said, and he grew angry. He blamed his wife for causing the rift in their marriage. He said she was violent. He claimed she beat their son, drugged him, refused to feed him. She might have been on drugs herself, he said. He claimed his wife told him once that she didn’t care if their son lived or died. She had driven the boy, he said, to the point of contemplating suicide.

He disagreed with the medication the child’s psychiatrist had prescribed and demanded that his wife quit giving it to him, but she ignored him. He found the prescription bottles that morning.

“It threw me into a rage,” he said. “I felt beside myself. I was angry.”

He told police that he said nothing to her before he shot her, and she said nothing to him.

An engineer from the company that made the crossbow, a Barnett Wildcat C5, testified that it shoots an arrow at a speed of 320 feet per second. In laymen’s terms, he said, it can span an entire football field in one instant.

Marx then took the bow apart and threw the parts away as he made his way back to Florida to meet his girlfriend.

Marx’s attorneys grilled the investigators over whether their method of interrogation, alleging that police promised him he could see his son if he’d say what they wanted him to say.

Prosecutors called the child’s psychologist, Dr. Carlos Kronberger, to rebut Marx’s claim that his wife was a violent person. Kronberger said he agreed to testify to spare the child from having to do so, but told the court he was limited in what he could say by privacy laws.

Psychologists are mandated by state law to report any suspected child abuse. He testified that he never reported Mary Marx, suggesting that the child never gave him reason to believe she was abusive or neglectful.

In fact, it was the opposite, Kronberger said: After his mother was killed, the boy revealed that his father had abused him, he said. He did not detail the specifics of that alleged abuse.

Prosecutors offered tapes of jailhouse phone calls Marx made to his girlfriend to hint at a different motive for the killing: money. He’d told police that she’d threatened to take half his pension if he left her.

In the recorded calls, he called his girlfriend, Michele Conry, pet names like “sweetie” and “darling.” He mentioned his wife’s $100,000 insurance policy.

“I just wish you would have convinced me to get a divorce,” he said in one. “I feel so sorry. Money doesn’t mean a damn thing. None of it does. I would have given it all up to be with you.” Editor’s note: This story was changed on Dec. 5 to reflect that Dr. Carlos Kronberger is a psychologist, not a psychiatrist.