Caleb Gordley wanted to go to a party Saturday night. But the 16-year-old was grounded because he hadn’t cleaned his room. So he decided he’d sneak out of his Loudoun County house to be with his friends.

When he left the party about 2 a.m., Caleb needed to sneak home. His friends dropped him off and helped hoist him through a back window. But Caleb had been drinking and had gone to the wrong house. The brick homes on his street are similar, and Caleb was two doors down from his own.

The homeowner heard his burglar alarm sound, grabbed his gun and went to investigate. When the two met on the stairs inside the house, the man said he told the teen to leave and fired a warning shot, according to a law enforcement official with knowledge of the investigation.

Caleb didn’t stop, and the home-owner fired again, striking and killing the teen, the official said.

A day later, Caleb’s friends and family were trying to figure out how this promising, well-liked athlete, who stayed out of trouble and generally listened to his parents, could have died in such a way.

“They have the exact same staircase as us, the exact same carpet. Caleb clearly thought he was in his own house,” said his father, Shawn Gordley, who provided the account of his son’s night. “He probably stumbled around and was just trying to go to his room.”

The home where the shooting occurred belongs to Donald West Wilder II, according to neighbors and real estate records. People on the block said that Wilder is a good neighbor who has lived in the home for about nine years and has been a Sterling volunteer firefighter for nearly two decades. Wilder did not respond to several attempts to reach him Sunday and Monday.

Police said the investigation continues. They said there is no indication that there was any animosity between the families or even that they knew each other. No charges have been filed.

Virginia law is largely silent on when a homeowner can shoot an intruder. But years of legal precedent give wide latitude to people who fear for their safety when someone breaks into their homes.

At Park View High School in Sterling, where Caleb was a junior and played basketball, football and baseball, students on Monday wrote memorial messages on a strip of butcher paper stretched across the gym floor. Many wore black and orange, the colors of the Cincinnati Bengals, Caleb’s favorite football team. The school observed a moment of silence, and grief counselors were on hand.

Members of the basketball team wrote letters to Caleb and watched team videos that showed the teenager high-fiving everyone around him. Caleb had gotten pulled up to the varsity team this year and often stayed after practice for extra help, his coach, Mike Koscinski, said.

“He was the hype man. He got everyone hyped up before games,” Koscinski said.

On Caleb’s Twitter account, he complained in recent weeks that there weren’t often parties in Sterling; he said there should be one every weekend. Then, on Saturday night, he expressed excitement that a friend was hosting a party.

“Turn up at Charlie’s house!!!! Ayeeeee,” he posted.

Early the next morning, friends dropped Caleb off on Pullman Court, a quiet cul-de-sac, and helped him through the window.

On Sunday morning, Shawn Gordley said, he got a call from the father of one of Caleb’s friends, who said the teenagers had been to a party the night before. Gordley said he went to Caleb’s room and found his son was missing. Then he learned that Caleb’s friends had driven him home.

Gordley had already heard there had been a shooting on his block. His heart sank. Frantic, he ran to the nearby house, pieced together what happened and called police.

“This is a kid who has never been in a fight,” Gordley said of his son. “Never been in trouble in school.”

Caleb lived with his father and his sister, Eden. Together with Caleb’s mother, the family released an emotional statement Monday: “Between the darkness and him being under the influence of alcohol, his mistake turned into the ultimate tragedy.”

Caleb’s family and the homeowner’s family barely knew each other, according to friends and relatives. There was just one house between them, but Caleb had lived there only about a year.

On Monday, social media sites carried tributes to Caleb and memories, many from teammates on the football, basketball and baseball teams. Some recalled how he joked around with friends, teasing them to make them laugh.

Caleb’s cousin, Joey Guyton, said Caleb was interested in science and technology and stood out as a smart kid. He also had a passion for music and would write and record original songs often under the name “Prince George,” his parents said.

“He had a bright, bright future, that’s for sure,” Guyton said.

Ferris Eways, the football coach at Park View, said Monday was a difficult day at school. He said Caleb was a good student and athlete and a leader among his peers.

“He’s a kid with a smile on his face all day long,” Eways said. “Great kid. Good to his friends, good to his teachers, and behavior-wise an outstanding student. Never ever complained, never ever did anything disobedient.

“It was an accident,” he said. “Teenagers make mistakes, and it was an accident.”

James Arkin, Caitlin Gibson, Tom Jackman, Julie Tate and Preston A. Williams contributed to this report.