It was early July and a serial killer was attacking homeless men in their sleep.

Patrick Brady walked past a surveillance photo of the suspect tacked up near the elevators in the lobby at Alpha Square, an East Village apartment complex for homeless and low-income people. When the elevator doors opened, Jon David Guerrero walked out.

A bulletin board in the lobby at Alpha Square, an East Village low-income housing project, displays notices and events. Before Jon David Guerrero was arrested in the series of homeless attacks in July, a surveillance photo of the suspect was pinned on the board. David Hernandez

The 39-year-old, who mostly went by his middle name, would later be arrested, accused of using railroad spikes and a hammer to brutally kill three homeless men and critically injure two others in the 12-day spree of attacks.

That day in early July, Brady entered the elevator. As the doors closed, Guerrero suddenly stuck his head into the elevator and jumped back inside. He had been acting strangely over the last few weeks, and was covered in sweat, Brady said.

“Either he was high or he had just gotten done with one of those killings,” the 55-year-old said.

Since that elevator ride, Brady hasn’t shaken the feeling that Guerrero was the killer police were after.

Guerrero, who will be evaluated by a court-appointed psychiatrist to determine if he is mentally competent to stand trial, seems to have have led a reclusive life, troubled by crimes and mental illness.

A homeless man with one of the flyers police were passing out to discover if anyone could identify the suspect in the attacks on other homeless men. — Peggy Peattie / San Diego Union-Tribune

A Coronado native, Guerrero’s grubby getup in high school led to the nickname Grubbit. Former Coronado High School classmates said he was often shoeless, shirtless and dirty. He liked to surf, and hung out with people who smoked pot and did other drugs, old classmates said.

After high school, Guerrero, who graduated in 1995, was in and out of Coronado until he moved away around 2000. Before he left, he had a child with a Coronado woman three years younger than him. Former classmates said he's never been a part of the child’s life.

The woman did not respond to requests for an interview.

Mental troubles and the law

Guerrero’s mental illness took full hold of him when he was about 22, according to court records. It also marked the onset of his criminal history. In cases from 1999 to 2001, he was convicted of burglary, grand theft and possession of stolen items.

Then, in 2008, he plead guilty to charges of burglary, grand theft and possession of marijuana and narcotics paraphernalia. Kathleen Guerrero wrote several letters to the court, saying her son didn’t do well on probation because he had trouble following directions and keeping track of time and appointments.

She tried to get him psychiatric treatment in jail, expressing concerns that, without it, he would revert to previous self-destructive behaviors. One symptom: He would “insert foreign objects into his body orifices.”

Guerrero was again arrested in 2009 and pleaded guilty to robbery for knocking down a homeless woman and stealing her bicycle several times. While on probation, he violated the conditions, was found not mentally competent and sent to Patton State Hospital.

In arguing for a lesser sentence, his attorney wrote that Guerrero hears “good and bad voices” when his medication wears off, but that he could live a normal, productive life on appropriate medications.

Records show mental health cases filed in 2008, 2009 and 2011. Court records say Guerrero suffered from schizophrenia and was considered disabled. At one point he was receiving monthly injections of Haldol, a type of anti-psychotic medication.

Jon Guerrero's arraignment was suspended Tuesday so a psychiatrist could evaluate whether he is mentally competent. (A judge barred photographers from showing Guerrero's face out of concern for tainting witness identifications.) — David Brooks

Guerrero has lived in an independent living facility, and, more recently in downtown San Diego. He lived at Hotel Metro, a low-income housing project, for about two years. Residents there dubbed him "Farmer John" because he grew marijuana in his room. At the time he had a vehicle, provided by his sister, and seemed content.

Brady, who considered Guerrero a good friend at the time, said he started keeping to himself when residents at Hotel Metro were relocated to Alpha Square, on 14th and Market streets, upon its completion in January.

Residents there described Guerrero as a recluse who didn’t make much of an impression. Most recall only a handful of encounters.

Sculptures fashioned with hammer

About a month after residents moved into the new studios, Guerrero started a petition to get internet service for residents. Some recall he tried to collect the 50 signatures the staff requested to consider the proposition but came up short, likely because residents would have had to pay for the service.

Dameon Ditto met Guerrero at Metro Hotel, where the two only greeted each other in passing. It was at Alpha Square that the fifth-floor residents became relatively close, particularly after Guerrero began taking Ditto’s art classes, which are free to residents, in April. Ditto described Guerrero’s art as “dark.”

His artwork depicted “skeletons, black mountains ... Some stuff that scared me after the fact,” Ditto said. “I didn’t really think much of it at the time.”

A bicycle and backpack lay in the street on West Laurel Street where a man was taken in to custody in connection with a series of attacks on homeless people. — John Gibbins / San Diego Union-Tribune

Guerrero showed a particular creative interest in rocks, turning beach stones and shells into Flinstones-like car figures, Ditto said.

To fashion the handmade cars, Guerrero presumably used a large hammer-like tool Ditto saw him carrying.

“I figured he was using that to chip away rocks,” Ditto said, adding it was customized with tape. “It seemed like he bought it in a certain way and then fixed it to a way he was comfortable using it.”

On Tuesday, Deputy District Attorney Makenzie Harvey said Guerrero is suspected of using a hammer and railroad spikes to kill or maim the five victims while they were sleeping.

On July 6, Angelo DeNardo, 53, was found dead in Bay Park with a spike driven into his head and chest, Harvey said. DeNardo was then torched.

The next day, Manuel Mason, 61, had a railroad spike driven into his sinus cavity in the Midway District. He survived but was rendered blind, Harvey said. Less than two hours later, Shawn Longley, 41, was slain in Ocean Beach.

ATTACKS ON HOMELESS

On July 6, Dionicio Vahidy, 23, was attacked in downtown San Diego. Witnesses heard loud noises and saw a man set another on fire. Vahidy died three days later.

The last victim in the series was found July 15 in Golden Hill, where a 55-year-old man was critically injured. A railroad spike was found near the site of the last three crimes, Harvey said.

RELATED: How the homeless attacks, arrests unfolded

An hour after the last attack, officers found Guerrero and arrested him. Police found a hammer, railroad spikes and the identification of two of the victims in the backpack Guerrero was wearing.

San Diego police investigators at the site under a freeway bridge in downtown San Diego where a homeless man was attacked Friday, July 15, 2016. — John Gibbins

That day, detectives spent hours combing through Guerrero’s studio, collecting bags of items, Alpha Square residents said. Harvey said police found a bucket that contained rocks, railroad ties and other spikes.

Bob McElroy, executive director of the Alpha Project, a homeless-services organization that runs Alpha Square, said residents were unnerved and dismayed to learn someone in their circle was arrested.

“Everyone knows each other,” he said. “They don’t all hang out, but they see each other. It’s a community.”

Perhaps no one was more affected than Guerrero's mother, McElroy said, describing her as a homeless advocate.

“She was there all the time, getting him food, giving him cards for Albertson’s across the street,” he said. “He not only murdered three people, he killed her too. She’s devastated.”

Guerrero’s parents did not respond to requests for an interview.

McElroy said it’s almost unbelievable that extra outreach teams worked with the homeless community to identify the killer, including plastering pictures inside Alpha Square, all while the suspect was right upstairs.

McElroy described Guerrero as quiet and polite, and compared him to “the Jeffrey Dahmers and the Ted Bundys of the world.”

“Unassuming, non-confrontational,” he said. “They are always the last ones you would think. People were totally shocked.”

Common patterns of serial killers

But Jack Levin, a Northeastern University professor who specializes in research on murder, prejudice and hate, wouldn’t put the assailant in the homeless attacks in the company of such prolific killers.

“The fact that the bodies were discovered immediately after death indicates this was not an organized killer,” Levin said. “The most skillful serial killers ... are the ones who take the time and effort to carry the bodies, sometimes more than 100 miles from the original crime scene.”

Levin said the man behind the homeless attacks might be better described as a spree killer.

“It’s unusual for a serial killer to kill three and injure two more over the period of two weeks,” he said.

The FBI defines a spree killer as a person who commits two or more murders without a cooling off-period, with some research defining that time frame as a month. Levin said spree killers have the tendency to be more frenetic.

“They are much more likely to suffer from a profound mental disorder,” he said.

But serial or spree, both varieties prefer to take the lives of their victims with their own hands, Levin said.

“They may bludgeon or stab, but they almost never use a firearm," he said. "That would only distance themselves from their victims.”

Despite the myth that serial or spree killers are psychotic murderers, that’s rarely the case. Very few killers, despite their seemingly crazed actions, have been deemed criminally insane, experts say. If the homeless attacks were linked to some kind of psychotic breakdown, that would actually put the killer in the minority, Levin said.

Guerrero’s mental state notwithstanding, Levin said, he could have been at least partly motivated by a need to feel powerful or important. According to Radford’s serial killer database, more than 40 percent of serial killers were motivated by enjoyment stemming from thrill, lust or power.

“We see them as horrific crimes against humanity, but they see them as great accomplishments,” he said. “They collect mementos or souvenirs the way a baseball player would collect a homerun ball, except they collect body parts, or jewelry or underwear, in order to reminisce about the good times they had with their victims.”

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