(CNN) A man has been charged with murder in connection with the of killing a police officer and wounding of another officer in Pomona, California, the Los Angeles County Sheriff's Department said.

Isaias De Jesus Valencia, 39, was also charged with attempted murder of other peace officers, the agency said in a statement.

Police Chief Michael Olivieri identified the officer who was killed as Greggory Casillas, 30, a rookie still in field training.

"Gregg is a hero, a man to be looked up to," Olivieri said. "He left his family at home to protect yours and his ultimate sacrifice will never be forgotten."

We are deeply moved by the love and support we have received from our law enforcement brothers and sisters, our community and people across the US during this difficult time. Our hearts are heavy as we mourn the loss of our brother, Officer Gregg Casillas. pic.twitter.com/iCZph5DsvF — Pomona Police Dept. (@PomonaPD) March 11, 2018

Valencia was arrested after he barricaded himself in an apartment for more than 15 hours.