Sometime Monday, someone entered a Quartz Hill home, killed four people -- including two children and a NASA engineer -- and set the home ablaze.
A day later, authorities were called to another fire, this time at a home in the Antelope Valley town of Rosamond. There, officials found two bodies in what authorities have labeled homicides.
Authorities said Wednesday that the crimes did not appear to be related, but officials could not recall so many homicides in the Antelope Valley during such a short period in nearly two decades.
The spate of violence has caused concerns across the valley, particularly because the killers appear to be at large.
In Quartz Hill, the body of Joseph Ciganik, a NASA Dryden Flight Research Center employee, was found with those of three others in the charred home in the 43200 block of 45th Street West.
Sheriff's homicide detectives on Wednesday continued to try to unravel the mysterious quadruple slaying as friends and family set up a memorial for the four victims outside the partially burned ranch-style home.
Los Angeles County coroner's spokesman Ed Winter said the preliminary investigation suggested that Ciganek, 60, suffered trauma wounds sometime soon after he returned home from work Monday.
Winter said Ciganek, a management system analyst, could have been attacked with a knife, a gun or other weapon.
Ciganek lived with his wife, Jocelyn, who was not home at the time of the fire and was returning from her job at a nearby mall when someone started the blaze.
Sheriff's Lt. David Coleman said a relative of the wife, along with her son and daughter, was also living at the home. Friends and relatives identified them as Jenny Park and her children, Jamie, 13, and Justin, who was 8 or 9.
Ciganek's body was found in one bedroom, and the other three victims were found in another bedroom. Winter said that those three victims' bodies were badly burned and that arson investigators would determine whether an incendiary liquid was poured on them or in the surrounding area to ignite the blaze. The home itself was not burned throughout, but bedrooms were severely damaged in the blaze, he said.
Coleman said it was too early to say whether a random intruder was responsible for the crimes or whether the perpetrator was connected to the family.
"We aren't saying there is a maniac on the loose here," he added.
At the memorial outside the home in the older working-class Antelope Valley neighborhood, relatives of the victims left a note with photographs.
"Dear friends thank you very much for love and support due to the destruction of the house we are desperately looking for some more pictures of Jamie and Justin," read the note. It asked readers to send pictures to a family e-mail address. "Thank you again for your prays," concluded the note.
Friends of the older girl stopped by Wednesday to remember her and place flowers at the memorial.
Chelsea Whitaker, 14, said Jamie was a good friend who attended Joe Walker Middle School with her. "She was just an absolute sweetheart. She was one of the best friends a girl could have," Whitaker said
Cameo Dansereau, 13, who also laid flowers at the memorial, said Jamie set her sights on being lawyer. She recalled Jamie saying, "I want to get straight A's to be great lawyer and get a great job."
Ciganek had worked at Dryden for 18 years, according to NASA spokesman Alan Brown. "He was thought of very highly here," Brown said.
Among other tasks, Ciganek maintained a one-of-a-kind SR-71 Blackbird flight simulator that he had rebuilt and operated for almost a decade, Brown said. Though the high-speed spy plane was retired in the late 1990s, Dryden continued to fly one for testing purposes, and Ciganek's flight simulator was critical to keeping Blackbird pilots up to snuff.
"Employees who were close to him took it very hard," Brown said of Ciganek's death.
Meanwhile, in Rosamond, a different set of detectives were dealing with another fire and double homicide.
It started when firefighters from the Kern County Fire Department responded to reports of a fire at a trailer on the property.
Firefighters found the badly burned remains of a man in the trailer.
Then in the house they found the body of an elderly woman "who appeared to be the victim of a homicide," according to a statement by the Kern County Sheriff's Department.
The woman was identified as Evelyn House, 82. Her body was covered with rugs, Sheriff's Lt. J.R. Rodriguez said.
Officials declined to provide further details.
There have been rumors -- and some media reports -- that the Quartz Hill and Rosamond cases were related. But detectives said they had no evidence of that. "It is a big valley with a lot of unrelated events," Coleman said.