MOUNT HOPE, the Bronx (PIX11) — Before she was taken into custody for observation in connection with the deaths of her 3-year-old boy and an 11-month-old boy, a mom paced outside with her hands on her head, a witness said.

Francis Pimentel spotted the woman on Saturday night on Echo Place in the Bronx. He said she kept asking herself what she'd done.

"I see a lady that she was walking, like acting crazy," Pimentel said.

It was not the only sign of concern. One resident of the Bronx building, a woman who did not want to be identified, said she smelled smoke and heard yelling.

"I heard the father yelling 'help me' and I live on the second floor. It happened on the third," she said. "So I did notice when all the EMTs were coming. I went out to the hallway. I did see a puddle of water on the second floor so I was just trying to figure out what was going on with the building. And I heard 'help me, help me, help them.'"

Officers responded to a report of a “female acting erratic, but non-violent, with no weapons” around 7:20 p.m., Deputy Chief Louis De Ceglie of Patrol Borough Bronx said during a press briefing late Saturday. Police were told a woman was trying to burn items in the kitchen and found her in the third-floor apartment “acting irrational."

She was taken into custody without incident until the arrival of an ambulance, which transported her to St. Barnabas Hospital for evaluation at about 7:50 p.m. Before leaving for the hospital, officers were told by a family friend that the children were with their father, De Ceglie said.

A 911 call at 7:55 p.m. for the same location reported two children were not breathing. He said officers returned to the apartment and found the boys with multiple wounds.

De Ceglie said officers and a family member tried to resuscitate the children while awaiting an ambulance, which took them to NewYork-Presbyterian/Columbia University Irving Medical Center where they died.

A memorial grew at the scene on Sunday. There were balloons, candles and messages for the boys.

"Rest easy baby boys," one message read. "Gone too soon," read another.

One resident said while she didn't know the baby, the 3-year-old boy had played with her niece at the park. She described him as a "very happy kid."

Police continued their investigation on Sunday. Charges have not yet been filed.

"This is an incredibly heart-breaking and shocking tragedy," a spokesperson for the Department of Social Services said. "We offer our deepest condolences to all who have been impacted and stand ready to provide them with any support they need during this incredibly difficult time.”