NEWARK, N.J. - The sight of a 7-month-old baby stabbed repeatedly during an attack that left the child's mother dead shocked even veteran firefighters at the scene.

Among the first to rush into the lobby of a Jersey City high-rise after Tuesday's attack, Armando Roman said that he found firefighters cradling tiny Ivan Reyes, covered with stab wounds.

Roman, the city's fire department director, spoke to the baby softly in Spanish - "Look at me, little guy" - trying to keep him conscious as the infant lay motionless, his eyes darting around as he slipped into shock.

Four of the firefighters who responded had to be relieved of duty later that day because of the trauma, Roman said. Counselors were called in to help the department cope.

Roman said in his 29 years as a firefighter, nothing had affected him so deeply. Even for the hardened first-responders who have seen it all in New Jersey's second- largest city, the sight was too much.

"I don't know who, in their right mind, would perpetrate such a heinous crime like this," Roman said. "Particularly with an infant child that couldn't pick anybody out of a lineup."

Ivan remained in critical but stable condition yesterday after his previous day's surgery, Hudson County Prosecutor Edward DeFazio said. Police searched for the person or people who attacked him and killed his mother, Jacqueline Reyes, 27. They have no suspects and are unsure of the motive, DeFazio said.

DeFazio said that police were reviewing footage from surveillance cameras and asking the public to call with any tips. He said that Reyes' husband, Ivan Reyes, discovered the bodies of his dead wife and injured son when he came home for lunch around noon Tuesday.

"It's extremely sad to see a family ripped apart in this manner," DeFazio said.

The prosecutor said that Ivan Reyes is a maintenance worker in the downtown high-rise where the couple lived with their baby and 4-year-old daughter.