PORTLAND, Ore. -- The firebombing of a North Portland home has exposed the underworld of Asian gangs many we don't often hear about.
But experts say, area Asian gangs are expanding and becoming more visible.
The groups have typically been overshadowed by larger street gangs, like Crips or Bloods.
As police investigate Wednesday's firebombing of the home on N. Banks police are learning more about the gang that's reportedly behind the attack.
The homeowner claims a Hmong gang is trying to recruit his sons through intimidation. They've vandalized cars, sprayed the house with bullets and now the violence. No one was hurt in the attack.
"I think they are trying to scare me or give up and join them," he said.
Threats and violence are common gang recruitment tactic.
"That is that the way these gangs often work, is you join us or else, you are either with us or against us and using those intimidation factors brings other people in," Portland State sociologist Randy Blazak said.
Experts say, Asian gangs often go unnoticed. Unlike other street gangs, they tend to prey on their own community.
"Its a sort of insular world that a lot of people on the outside world don't have access to, including other gang members," according to Blazak. "I mean, it is often a mystery to other gang members like Bloods and Crips about how groups like Asian Cobras and those groups work."
Police records obtained by KGW detail another rare public incident in November, when gang members sparked a small riot at a Hmong New Year's festival in Hillsboro.
Police worry the once relatively quiet gangs are becoming more active and the violence more extreme and more public.
Police don't have an exact number of Asian gang members, but they figure it is a small percentage of the estimated 3,000 street gang members statewide.
KGW Reporter Kyle Iboshi contributed to this report.