An on-duty mail carrier was shot and killed in New Mexico after intervening in a dispute between a 17-year-old and his mother, police said.

Authorities in Albuquerque were hunting for suspect Xavier Zamora, who was accused of murder in a criminal complaint that says he allegedly shot mail carrier Jose Hernandez in the stomach on Monday.

The 47-year-old was shot in the afternoon in front of Zamora's residence on the southwest side of the city.

The suspect's mother, Roxanne Zamora, told police her son became aggressive with Hernandez after he tried to help diffuse the domestic dispute, prompting the USPS mail carrier to use pepper spray on the teen, according to the criminal complaint.

Zamora went into the house after the encounter then returned a short time later, shot the Postal Service worker and ran back into the house, according to his mother said.

Mailman Jose Hernandez (left) allegedly died after intervening in a dispute between 17-year-old suspect Xavier Zamora (right) and his mother outside their house in Albuquerque, New Mexico

SWAT officers secured the neighborhood during an hours-long stand-off at the house, believing Zamora might still be inside.

None of the witnesses who were in front of the home with Hernandez after the shooting reported seeing Zamora leave the home, police said on Tuesday.

The Postal Service identified Jose Hernandez as the victim, saying he has worked for the service for 12 years.

Rod Spurgeon, a spokesman for the Postal Service: 'This is something that is completely unexpected.'

Alex Perez heard the gunfire and rushed outside to find Hernandez on the floor.

He told told KRQE: 'When I opened my door, the first thing I saw was the mailman on the floor.

New Mexico Police said in a criminal complaint that Jose Hernandez was fatally shot on while trying to intervene in a dispute between a mother and her 17-year-old son, who has been identified as the shooting suspect

His daughter said Mia Perez, added: 'He always had a really big smile on his face and he would like.. always wave at everyone. We knew him, he had a really big heart.'

Other neighbors who knew Hernandez are in shock at the killing of the father-of-four.

Michael Shephard told KRQE: 'How it ended up, it was the wrong way to go with him. He was doing the right thing, and somebody took his life for no reason.'

Zamora's home was left with broken windows and large holes after the SWAT team tried to get the suspect to come out after the shooting.

Mayor Tim Keller said in a statement the shooting had shaken the city, where more than two dozen homicides have occurred since the start of the year.

Flowers and notes are arranged atop a mailbox on Tuesday in tribute to a mail carrier who police say was killed outside an adjacent home in Albuquerque

He said: 'The men and women who carry our mail day-in and day-out are public servants in every sense of the word.

'We know we must, and will continue to, fight against the gun violence that has taken a terrible toll on our community.'

Zamora is now charged with an open count of murder and has a warrant out for his arrest, police said.

The FBI have taken over the investigation because Hernandez was killed on his job as a federal worker.

Spurgeon referred questions about the investigation to the U.S. attorney's office, which did not immediately respond to requests for comment.