A bomb squad descended on a quiet street of ranch homes in the Orange County city of Costa Mesa after the 52-year-old man died in a Sunday night blast.
An ambulance had been called about 90 minutes earlier when neighbors saw the man lying on his front lawn and he refused offers of help.
Police were called about 7:30 p.m. after neighbors heard the explosion, and the man was found dead at his home.
Police suspect he was killed by some sort of homemade explosive.
At least two other explosive devices were later found at the home, police Sgt. Jerry Hildeman said.
Neighbors from surrounding homes were evacuated and remained out of their homes Monday morning. They will be allowed to return when the house is declared safe, police said.
The FBI, an Orange County Sheriff’s Department bomb squad and other agencies responded to the scene.