The situation started to unfold around 5 a.m. at a home on the 1200 block of W. 17th Street, where officers tried to contact a felon who they believed was armed.
SWAT officers surrounded the home after the people inside refused to cooperate with law enforcement. Authorities learned there were six people inside the home ranging in ages from 15 to 75.
When officers finally gained entry into the home, they found a stash of high-powered weapons as well as a pound of methamphetamine. Investigators said the weapons recovered at the home included two military-style assault rifles, a grenade launcher and ammunition.
All individuals exited the house without incident shortly after 9 a.m.
Fontana police said three adults - two men and one woman - were arrested for narcotics and weapons charges. Three others, including a grandmother in her 70s, were questioned and released. Investigators identified the primary suspect as 20-year-old Jorge Alvarez. The children inside the home were released to their parents, who were not inside the house at the time of the barricade.
Ten area homes were evacuated as a precaution.
"I woke up around 5 o'clock and my mom woke me up, and I went in the living room, and they tell me they were raiding someone's house. I looked and it was my neighbor's house. I was just shocked," said area resident Justin Serna.
Neighbors said police have been called to that home before.
The San Bernardino Police Department and the Inland Valley SWAT team, comprised of officers from the Colton, Fontana and Rialto police departments, were involved in the investigation.