ATLANTA -- A two-year-old and his father died Wednesday night after the man shot the boy and then himself at the end of a more than 18-hour standoff in Atlanta's northeastern suburbs, police said.

Thy Ho, 43, and son Philip Nguyen were each found with a gunshot wound when authorities entered the master bedroom of the Buford home after hearing gunfire about 4:40 p.m. Wednesday, Gwinnett County police Cpl. Michele Pihera said. Pihera said the father shot himself when officers entered the room.

Both were taken the hospital in critical condition, Pihera said, and later died.

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CBS affiliate WGCL reported the standoff began with a domestic dispute around 10 p.m. Tuesday night with a 911 call reporting that a man threatened to shoot everyone at the home and then take his own life.

A female and "several other people" were eventually allowed to leave the home, but the toddler remained inside with the suspect, police said.

A SWAT team sealed off the neighborhood in a subdivision about 35 miles northeast of downtown Atlanta.

"It's very scary because nothing ever goes on here," neighbor Melanie Trammell told WGCL. Some neighbors were forced to spend Tuesday night in their cars.

Johnny Cook was one neighbor who was stranded outside his neighborhood. He told WGCL he wasn't concerned about that, only the child.

"Yeah I'm hoping the child come out safe, and I guess he let some people out last night and I'm glad he let them out," Cook said at the time. "I'm hoping someone can talk him into coming to his senses and doing the right thing."

Police announced that residents were being allowed back into the neighborhood Wednesday night as investigators continued to process the crime scene. Gwinnett County medical examiner will determine the official causes of death.

Wednesday was the first day of a new semester in the county's schools after the holidays but school buses were not allowed into the neighborhood, school system spokeswoman Sloan Roach said.

The standoff came one day after police in nearby DeKalb County said a man with a knife held 11 children and his girlfriend inside a motel room for five hours before stabbing himself in the neck Tuesday morning. The man was critically injured No one else was hurt.