This undated photo provided by the Arizona Department of Corrections shows Ryan Giroux. A rampage Wednesday, March 18, 2015, included a motel shooting, a carjacking and a home invasion and ended with his arrest at a nearby apartment in suburban Phoenix. Police later identified the man as Giroux, an ex-convict who has served three stints in state prison since 1994. (AP Photo/Arizona Department of Corrections) Ryan Giroux’s 2012 mugshot. (Arizona Department of Corrections via AP)

His eyes are big. His head is shaved. The number 88, code for “heil Hitler,” inks his left temple. The words above his eyebrows are black and unmistakable.

“SKIN HEAD.”

This is Ryan Giroux in his 2012 mug shot. He is now 41 years old. He has been in and out of prison since he was a teenager on a string of felony convictions from aggravated assault to drug use to burglary. That list of felonies may soon soon swell after Wednesday’s carnage.

At a small motel in Mesa, Ariz., outside of Phoenix, the shooting started mid-morning on Wednesday. An apparent argument gave way to a shooting spree that ultimately left six people injured and one dead. The initial barrage of gunfire led to a carjacking and additional shootings that appeared to be random. Hours passed before police using a stun gun arrested a man they identified as Giroux, returning him to a familiar habitat: a cell.

Police say one person was killed and five more wounded in a shooting spree in a Phoenix suburb before the suspect was taken into custody Wednesday. (Reuters)

Authorities haven’t released the names of any of the victims, several of whom are in critical condition. Police said they have no reason to believe a hate crime was committed. It’s also uncertain what caused the argument.

“He’s a violent guy,” one local detective, who recalled Giroux from when he infiltrated a local skinhead movement, told the Southern Poverty Law Center, which keeps the most complete database of hate organizations. “I think his time in prison contributed to that.”

The anonymous police source told the center that Giroux was a member of a notoriously brutal, diffuse organization named the Hammerskin Nation, which the Anti-Defamation League called “the most violent and best-organized neo-Nazi skinhead group in the United States.” It spans more than a dozen countries and broke into national headlines in August 2012. That was when one of its adherents perpetrated a mass shooting at a Wisconsin Sikh temple.

The group illustrates the surprising resilience of the American hate group. Other aging hate groups have lost membership as prospective recruits opted for anonymous online forums, according to the SPLC. But the Hammerskins have retained a strong online presence, their Web site clogged with tens of thousands of posts.

The roots of the Hammerskin Nation go back decades. The 1979 Pink Floyd album “The Wall” provided the group its name and symbol, reported the Anti-Defamation League. “The swastika is replaced by Pink’s symbol: two crossed hammers, which he boasts will ‘batter down’ the doors behind which frightened minorities hide from fascist supporters. … The Hammerskin Nation has made real the gruesome fantasy … racist music and racially motivated violence under a banner bearing two red, white and black crossed hammers.”

Other groups that came up decades ago — like the Ku Klux Klan and the Aryan Strikeforce — have been decimated by the digital era. Membership across older groups like these is declining. As The Washington Post’s Sarah Kaplan pointed out, the number of Ku Klux Klan chapters plummeted by nearly half in 2014, from 163 to 72.

[The state of hate in America: A new home on the Internet]

Hate now stalks online forums, where its denizens guard their identity with pseudonyms. This is where Hammerskin Nation has separated itself from its competitors. Its vast, labyrinthine network of online chat rooms provides members with a forum to exchange racist jokes and share tips on anything from “Mein Kampf” to “parenting, cooking, homeschooling and other home and family-related topics.” You need to first apply for acceptance to these forums.

Its users are wise to the dangers of hackers. “Do not assume this forum is secure,” one rule section advises. “… Our government can put a nuclear warhead on a dime anywhere in the world. If you think they can’t access your accounts on the Internet, you’re dead wrong.”

Meanwhile, the Ku Klux Klan operates an antiquated Web site, and the Ayran Strikeforce barely has one.

The anonymity afforded by the Hammerskin Web site attracted men like the Wisconsin shooter. He was an avid participant in Hammerskin Nation discussions inside those forums. According to the Milwaukee Journal-Sentinel, he posted to the group more than 200 times under the handle “End Apathy.” “Awesome show this weekend!” he wrote in one message about a concert he played. “It was great to meet/see so many people. Great times, no static, no bs. This is how a skinhead show should be.”

Hammerskin’s online presence reflects broader trends in modern American hate. “There is little to attract radicals to join groups when they can broadcast their opinions across the world via the Internet and at the same time remain anonymous if they wish,” the SPLC report said. In other dark corners of the Internet, “many extremists congregate anonymously in password-protected forums.”

It’s unclear how active — if at all — Arizona’s Ryan Giroux was in these sort of groups. It’s entirely possible he was more interested in the group’s history of violence than chat rooms, as shown in police records. “By the defendant’s own admission, he has the propensity to become violent when he is either intoxicated or using illegal drugs,” the Arizona Republic reported his probation officer wrote last year. “He has a long arrest history that demonstrates violent behavior.”