LAKELAND, Fla. (WFLA) — A Marine wielding an automatic weapon went on an early-morning shooting rampage in Lakeland, killing four people, including an infant inside their home, authorities said Sunday. One person, an 11-year-old survived the attack, and was rushed to the hospital in critical condition. She is said to be in stable condition Tuesday morning.

“It was continuous, pop, pop, pop, pop, pop,” a neighbor who heard the gunfire said.

Bryan Riley, 33, the suspected shooter, opened fire on responding deputies before being taken into custody. No deputies were seriously hurt in the incident, authorities said.

Riley, a Marine and sharpshooter, had done tours in Iraq and Afghanistan, and was honorably discharged. According to the sheriff’s office, Riley lived in Brandon, about 30 minutes from where the shooting occurred. It’s still unclear why he targeted the family.

Investigators say that when they captured Riley outside the home, he told them, “You know why I did this.”

But they say they don’t and, in fact, may never know why Riley launched an attack against a family he had no known connection with, except that he may have been mentally ill. Riley’s girlfriend told investigators that he had been saying he could communicate directly with God.

“The big question that all of us has is, ‘Why?’” local prosecutor Brian Haas said after Sunday’s slayings. “We will not know today or maybe ever.”

Riley, 33, is being held without bond after Sunday’s massacre on four counts of first-degree murder. During his first court appearance Monday, he said he intended to hire a lawyer but a public defender was appointed to represent him until he does.

According to Polk County Sheriff Grady Judd, Riley told interrogators that the victims “begged for their lives, and I killed them anyway.”

”He is evil in the flesh,” Judd said. “Just because you have mental health issues, does not mean you are not criminally liable.”

Judd identified Justice Gleason, 40, as one of the victims. Citing a state privacy law, Judd only identified the other victims as a 33-year-old woman, her infant son and the boy’s 62-year-old grandmother. Facebook posts and public records show Gleason was in a relationship with Theresa Lanham and they had a baby boy, Jody, in May. Lanham’s mother, Catherine Delgado, owned the property and lived there. Gleason also had an 11-year-old daughter from a previous relationship.

According to Judd and court records, on Saturday evening, about nine hours before the attack, Riley stopped his truck and confronted Gleason as he mowed his lawn. Riley, who lives 30 miles away in Tampa (50 kilometers), told Gleason that God had sent him to prevent a suicide by someone named Amber.

Gleason and one of the other victims told Riley no one by that name lived there and asked him to leave. They called 911, but when authorities arrived, Riley was gone. A deputy searched the area, but didn’t find Riley. Judd said given the circumstances, there wasn’t much more that could be done.

“We get thousands of reports of suspicious people,” Judd said. “To suggest that we’ve got time to stop and do an investigation of every suspicious vehicle is not possible. He made zero threats. He was just a guy that was saying some really goofy stuff.”

Riley returned around 4:30 a.m. Sunday, arranging glowsticks to create a path leading to the house in what Judd said may have been an attempt to draw officers “into an ambush.”

Shooting soon began — and when a deputy in the area heard popping noises, he sounded the alarm, bringing state and local law enforcement officers to the scene. When they arrived, they found an apparently unarmed Riley outside, dressed in camouflage, and his truck ablaze.

But Riley ran back into the house, where authorities heard more gunfire, “a woman scream and a baby whimper,” Judd said.

Officers tried to enter the house, but the front door was barricaded. Judd said when they went to the back, they saw Riley, who appeared to have donned full body armor.

Riley and the officers exchanged heavy gunfire, with dozens “if not hundreds of rounds” fired, before Riley retreated back into the home, Judd said.

Everything fell silent, until a helicopter unit noticed that Riley was coming out, the sheriff said. He had been shot once and was ready to surrender.

Officers heard cries for help inside but were unsure whether there were additional shooters and feared the home was booby-trapped. Still, one officer rushed in and grabbed the wounded girl, who told authorities there were three dead people inside.

The sheriff’s office said they all had been huddling in fear, with the boy dying in his mother’s arms. Even the family dog was shot dead.

“I will never be able to unsee that mother with that deceased infant in her arms,” Judd said. “It is a horror of the utmost magnitude.”

Family friend Pansy Mincey Smith told The Ledger she last saw Gleason at the hospital shortly after his son was born.

“You were smiling from ear to ear about your new little baby boy, you had that big teddy bear for him. This is so heartbreaking,” Smith wrote on Facebook.

Authorities said Riley’s girlfriend told investigators he was never violent but had become increasingly erratic. She said he claimed to be on mission from God, stockpiling supplies for Hurricane Ida victims including $1,000 worth of cigars.

Riley’s vehicle had also been stocked with bleeding control kits and other supplies for a gunfight, authorities said.

He worked as a private security guard and had no criminal history, the sheriff said.

Officers took Riley to jail in a white jumpsuit later Sunday. He appeared downcast, hanging his head and hardly opening his eyes, as reporters asked why he killed the family.

“This guy was a war hero. He fought for his country,” Judd said. Now, ”he’s a cold-blooded killer.”

Riley told detectives he shot people on this property because ‘God told him to.’ He called himself a ‘sick guy’ and said he wanted to go to jail.

Some who knew Riley told 8 On Your Side that they never saw any red flags, but others saying they did.

Riley’s neighbors in Brandon said he always seemed nice.

“Nothing [wrong], always welcoming and his parents, [are] very nice people. I just, I just don’t know,” said German Barreon.

But Riley’s girlfriend said she did recently notice concerning behavior.

Sheriff Grady Judd said Riley served in the U.S. Marines Corp. and was deployed to Iraq and Afghanistan before being honorably discharged.

The sheriff said Riley’s girlfriend told investigators he suffers from PTSD, and recently claimed he could talk directly with God.

Sheriff Judd told us Riley’s girlfriend believed his behavior had become increasingly erratic.

She said he was a security guard at a church and came home saying he could talk to god.

She said he went out and bought a thousand dollars worth of cigars to help hurricane victims. But she never saw him act violently.

A Polk County Sheriff Forensic Unit remained at the scene Tuesday morning when 8 On Your Side’s Christine McClarty went to the home.

Miguel Rivera lives a few houses away. He told 8 On Your Side he was convinced Riley knocked on his backdoor moments before going across a vacant lot and murdering the family.

“God bless that family, all that happened to them, I was thinking about mine. What would have happened if I would have opened that door?” Rivera said.