A 7-year-old Plymouth boy fatally shot himself after finding a loaded handgun stashed with a toy in the family’s home while other children played nearby.

Keyaris Samuels died in the Wednesday afternoon incident. Authorities said the children, ages 7 to 11, were playing without an adult at home when one of them found the gun in a box in the bedroom. The box also held a new hoverboard.

All four children saw the gun, and Keyaris was inside alone with it when the other three children, who went outside, heard it go off.

Keyaris’ mother arrived home shortly after the shooting, according to Plymouth Public Safety Director Mike Goldstein. She told police she was unaware the gun was in the box and that it was not hers. Goldstein said it’s possible that Keyaris believed the gun was a toy like the hoverboard.

“This entire incident should have never occurred,” Goldstein said. “No one should have died, especially such a young and innocent child.”

Goldstein said police were interviewing people to determine who owns the gun.

“We will do everything in our power to hold the gun owner or owners accountable for their irresponsible and unconscionable actions,” Goldstein said.

“I am so sad for this family. … Everything we were told is that Keyaris was a sweet little kid.”

Keyaris was a first-grader in the Wayzata school district, according to a statement from the superintendent.

“This is certainly a challenging time for all of us at Wayzata Public Schools and throughout the broader community,” the statement from Superintendent Chace Anderson read. “With challenging times like this, it is important for us to pull together in support of one another.”

Anderson said additional support staff has been added at the school to offer anyone assistance coping with “this tragic news.”

The shooting occurred shortly after 3 p.m. at Common­Bond Communities’ Vicksburg Commons, a townhouse complex on Shenandoah Lane N., police said.

Officers arrived to find the boy bleeding from the head upstairs in one of the units, according to emergency dispatch audio.

Emergency responders began resuscitation efforts, but Keyaris was pronounced dead at the scene. Goldstein said the Hennepin County medical examiner would release more details.

A memorial on the front steps of the townhouse grew Thursday, including flowers, a photo of the smiling boy in a white suit, teddy bears and other stuffed toys.

An older cousin who declined to be identified called Keyaris “the sweetest boy ever, just full of life, loved his family … not a bad bone in his little body.”

“It really hits home because I have a 12-year-old son of my own,” said neighbor Susanna Kallin. “It’s just unbelievable. He was a good kid.”

Sandie French of Brooklyn Center said her nieces played with Keyaris, although they were not there when the shooting occurred.

“They are devastated,” she said. “They are going to have to seek counseling.”

There have been at least 70 unintentional shootings by children across the United States so far this year, according to Everytown for Gun Safety, a gun violence prevention group. Among them, 19 were fatal.

Keyaris’ death is at least the third Minnesota shooting involving a child’s discovery of a loaded gun. In 2012, a 2-year-old St. Paul boy survived a gunshot to the forehead after his 9-year-old brother got a loaded gun from an unlocked cabinet and accidentally shot him. Their father, Lue Xiong, was convicted of negligent storage of a firearm, a gross misdemeanor.

The same year, 2-year-old Neegnco Xiong was fatally shot in the chest by his 4-year-old brother, who had found a loaded handgun tucked beneath a mattress. It was one of eight guns in a house where four children lived. Their father, Kao Chongsua Xiong, was convicted of second-degree manslaughter and child endangerment and received probation.

In 2013, a 9-year-old Oakdale girl was injured after her 5-year-old brother picked up a .22-caliber rifle and accidentally shot her in the chest.