Ramos, who said on his Facebook page that he attended Santa Rosa High School and is a carpentry foreman, is the father of two children and one grandchild. He says on the page he is from San Nicolas, Ilocos Norte, Philippines.
Ramos is the subject of criminal and family law cases dating back to the 1990s, with charges including domestic violence, DUI, theft and battery, records show.
Ramos also has a record in federal court files for a traffic stop in 2011 that led to the seizure of marijuana and more than $26,000 in cash.
He has a pending case in Sacramento Superior Court charging him with battery against a minor, and police say the incident that led to O’Sullivan’s death began with a domestic dispute.
O’Sullivan was helping a woman remove her belongings from a home on Redwood Avenue Wednesday night when a gunman opened fire and killed her, then held police and the neighborhood under siege before surrendering.
Ramos is being held in the Sacramento County Main Jail without bail and faces his first date in Sacramento Superior Court Monday afternoon.