A police officer who was hit at least three times in a shootout remains in critical but stable condition.Officer Robert Salerno was shot Monday while responding to a 911 call in the South Bronx. He was hit twice in the abdomen. His bullet-resistant vest blocked another bullet.He remained at Lincoln Medical and Mental Health Center on Tuesday.The shooting occurred around noon at a housing project. A home health care aide called 911 to say her client's son had a gun and had slapped her.The son, Santiago Urena, opened fire on police. Officers returned fire, shooting 21 times.Urena was later found dead inside with a gunshot wound to the head. It was unclear whether it was self-inflicted or from police gunfire.