Kassim Alhimidi, 48, was taken into custody Thursday after being called into the police station, said El Cajon Police Chief Jim Redman.
Police said there were no other suspects. Redman declined to comment on the evidence or elaborate on a possible motive.
“Criminal investigations build, evidence builds, and you reach a point where you have enough evidence to move forward, and that's what happened in this case,” he said.
Alhimidi went to Iraq for about two weeks to bury his wife and returned voluntarily, Redman said. Police did not try to prevent him from leaving the country because he was not a suspect at the time.
Kassim Alhimidi was publicly silent for six days after the body was found, while his children spoke often with reporters.
In his first public remarks – made at a news conference at the family's mosque in Lakeside – he demanded to know what motivated the killer.
He also urged anyone with information to contact law enforcement and thanked the Iraqi government for flying his wife's body to Iraq. He declined to answer reporters' questions.