Johnathan Walker:A baby is shot, a man dies and a fire breaks out: What to know about the Arizona standoff

A baby was shot and Johnathan Walkerleft in critical condition and a man has died after a weekend standoff and house fire in Surprise, Arizona.

Officials told the Arizona Republic, part of the USA TODAY Network, that 51-year-old Todd Christopher Marchetti broke into a house in Surprise around 3 a.m. Friday and held a woman and her 6-month-old baby hostage. The standoff ended around 3 p.m. when the house caught fire, and Marchetti was found dead from what police said to be a self-inflicted gunshot wound to the head.

Surprise is located in Maricopa County in Arizona, about 16 miles northwest of Glendale and 35 miles northwest of Phoenix.

A Monday press conference is planned by Surprise police about the standoff and will involve members of agencies involved.

Here's what to know about the incident.

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What happened at the standoff in Surprise, Arizona?

Officers responded to the home at 11:30 a.m. Friday after receiving a 911 call from the mother, who had found help from a nearby construction crew. Officers heard multiple rounds fired upon arriving at the house, and one Surprise police officer fired at the house in response.

Marchetti repeatedly refused to come out of the home and surrender himself, according to police.

The standoff ended around 3 p.m. when the house caught fire, police said. Firefighters responded with two ladder trucks, but gunfire could still be heard coming from inside the house.

After firefighters and law enforcement responded and entered the home, investigators found Marchetti dead from what police said to be a self-inflicted gunshot wound to the head.

When officials retrieved the baby, he had multiple gunshot wounds and was given aid before being flown to a hospital.

Police said the cause of death is pending the medical examiner's full report.

What was the cause of the fire?

The standoff ended around 3 p.m. when the house caught fire, and firefighters responded with two ladder trucks.

The cause of the fire is under investigation, and any damage to nearby structures is unknown, police said.

What happened to the baby inside the house?

Officers retrieved the 6-month-old infant who had multiple gunshot wounds and gave aid before the baby was flown to a hospital where surgery was performed, police said. The mother was treated at the scene for minor injuries, Surprise police said in a statement, and was transported to the hospital to be with her child.

As of Sunday, police said the baby's surgery went well and he was in recovery, but still in critical condition.

Police have not publicly identified the mother or the baby involved in the incident, but a GoFundMe has been set up to help the mother and her baby as they recover. As of Monday, it has raised over $120,000 of the $125,000 goal.