Joshua Aaron Robertson, 27, and Brittany Humphrey, 22, were last seen with Kimberly Harvill's children - Joslynn Watkins, 2; Brayden Watkins, 3; and Rylee Watkins, 5 - and have fled California, the Los Angeles County Sheriff's Department said in a news release.
Harvill, Humphrey's sister, was found dead in Gorman on Aug. 14 by a motorist who had made a rest stop on Gorman Post Road, just north of the 138 Freeway, in the northwest area of the county. Authorities initially said the body was found in Lebec.
Before Harvill was officially identified, investigators last week released a composite sketch of her face and asked the public for help in determining her identity. She was described as having tattoos on her body that included the names Rylee and Brayden.
"Help us get those kids home. We need them home because they've got a life that they should be able to live," said the godfather of the three children, Tso Yanez, in a tearful interview Tuesday evening. "I'm at a loss as to why this all went down, what actually happened."
A warrant has been issued for the arrest of both Robertson, who has a criminal history, and Humphrey, according to the sheriff's department. The pair were also wanted for questioning in Harvill's death.
Robertson "is on post-release community supervision and has a previous arrest for possession of a firearm," the news release said, adding that he should be considered armed and dangerous. He is Humphrey's new husband, according to her Facebook page.
Robertson and Humphrey were believed to be traveling with the three missing children in Harvill's green 1999 Ford Expedition SUV, which may have California license plate No. 7BEK024 or paper plates, authorities said.
The vehicle is described as having a rear sticker stating "R.I.P. Chad Watkins," a rear sticker of a six-person stick-figure family, and camouflage duct tape on the exterior base of the SUV.
"The kids already lost their dad ... through suicide, and now they lose their mom through murder," said Willie Venson Jr., Harvill's neighbor. "That's terrible."
Humphrey is said to be white, 5 feet 2 inches tall, weighing 120 pounds, with blond hair and blue eyes. Robertson is described as white, 6 feet 2 inches tall, weighing 170 pounds, with blond hair, blue eyes and tattoos on his right arm.
Anyone who sees the children or the suspects is asked to call local law enforcement by using 911, or Sgt. Ken Perry or Detective Scott Matlock of the Los Angeles County Sheriff's Department at (323) 890-5500. Those who wish to remain anonymous may call Crime Stoppers at (800) 222-8477.