RANCHO CORDOVA, Calif. — The violent deaths of an immigrant mother and her two young children have Northern California’s Slavic community recalling a similar killing spree a decade ago. But this time, community leaders say the warnings were apparent.

Grigoriy Bukhantsov, 19, remained in custody Thursday. He faces formal murder charges Friday in killing his 23-year-old sister-in-law, Alina, 3-year-old niece, Emannuela, and 2-year-old nephew, Avenir.