The tragic mix of a not-so-hidden hunting rifle and a child's naive curiosity ended Saturday in the shooting death of a 9-year-old by his identical twin brother.

"I just can't believe that this happened. I don't even usually keep the hunting rifle at our house, but I was going to try to sell [it] this weekend," said Michael Lanese of Upper St. Clair, father of Christian and Stephen.

A third-grader at Streams Elementary School in the Upper St. Clair School District, Christian Lanese died of a single shot to the head from the rifle at about 3:40 p.m. Saturday at his home on Eton Road.

Mr. Lanese and his surviving son, Stephen, sought comfort yesterday at their family's church, St. Louise de Marillac in Upper St. Clair, where the boys made their first Holy Communion last spring.

"Our priest really helped," said Mr. Lanese in an interview yesterday afternoon. "He talked to Stephen. He's feeling so horrible. Christian wasn't just his twin brother. He was his best friend."

The day unfolded as most Saturdays do at the four-bedroom, ranch-style home the father and sons shared in the quiet South Hills suburb, but for one fatal exception. Mr. Lanese said he had decided to sell his hunting rifle, a shotgun and a .22-caliber rifle at a local flea market in Bridgeville that day so he had retrieved the firearms from his brother's home where he had been keeping them.

"I had cleaned them up to sell them. I don't hunt anymore, so I figured I'd get rid of them," he recounted.

He and the boys went to the flea market about 10:30 that morning, but the crowd was sparse.

"I guess the cold kept everyone away. The guy I thought I'd sell them to wasn't there," said Mr. Lanese, an account executive for a hotel furniture company.

Upon returning home around 1:30 p.m., Mr. Lanese said, he hid the firearms in a closet in his bedroom, intending to return to the flea market the next day to make another attempt at selling them. Then, everyone went about their business.

Mr. Lanese said he ended up reading a book in the living room and, as far as he knew, his sons were playing video games on the television in his bedroom.

All of a sudden, he heard a "big boom."

"That's not a sound you're supposed to hear in your house. I ran down the hall and into my bedroom. Stephen was screaming and I saw Christian. I knew right away he was dead. He was shot in the head," Mr. Lanese said.

He learned from Stephen that he had gotten shells for the hunting rifle from a tool room off the garage in the basement and had loaded them because he was curious about the lever action of the rifle.

"I guess he saw something on TV. He wanted to see the lever action. It went off and his brother was standing in front of him," the father explained, noting that the gun fired as Stephen was trying to eject a shell. "I didn't keep the ammunition with the [weapons]. I didn't think they had access to the shells," he said.

Stephen ran screaming out the front door of the house and Mr. Lanese called 911 for help.

"I still can't believe it. Christian was eating rice and vegetables. He was in front of the bed. Now he's gone," said the father, who has been raising the boys on his own since he and his former wife divorced about three years ago after nine years of marriage. It was Mr. Lanese's third marriage.

Coincidentally, moments after the shooting, the boys' mother, Truc, who was born in Vietnam, arrived for a scheduled visit with her sons.

"She walked in in the middle of all this commotion. It was horrible," Mr. Lanese said.

Though he said he believes he and Stephen are still reeling from the shock of Christian's death and struggling with remorse, he said he believes they both eventually will be OK.

"We'll get through this. We'll get whatever counseling or help that we need," he said, noting that Stephen is a smart, resilient boy who had a special relationship with his brother.

"That doesn't die. They'll be together again some day and Christian will always be with Stephen. They didn't call each other by their names. They called each other 'brother,' They had their own bedrooms, but they preferred to sleep together. They held hands and took baths together. That kind of relationship doesn't die," Mr. Lanese said.

Christian was a boy mature beyond his years in many ways, his dad said.

"He had really great taste in food. He liked sushi and lamb chops," he said.

Likewise, he was accomplished as a cook.

"He loved to be in the kitchen. He'd be making a sauce for salmon or baking cookies," his dad said.

His culinary endeavors were well-known at school, as well, said Claire Miller, principal of Streams Elementary.

"We've heard him tell us many wonderful stories of the recipes he prepared at home. He would amaze the adults with his tales of cooking," she said.

She said Christian was known as a child with "gusto for life" who also was "quite artistic."

"He was a caring and special little boy who will be greatly missed by the students and faculty and families of Streams school," Dr. Miller said.

A boy of many and varied interests, he was as likely to join in a game of baseball or cook up a science experiment as he was to be baking a batch of cookies.

His enterprising ways didn't end there, though.

"He'd tell me he was making cookies and then he'd put up a stand outside the house and sell them for 50 cents apiece," said Mr. Lanese with a laugh.

Christian's favorite subject in school was math, though he did well in all academic areas.

"He was a very good student. He never missed school," said his dad.

Articulate and talkative, the boy was a cuddler who enjoyed snuggling with his dad and brother while watching TV.

"He was just a great kid. A lovable little guy," said his dad.

Mike Lanese of Polish Hill, Michael Lanese's son from his first marriage and half-brother to Christian and Stephen, said his deceased brother was "vibrant and healthy, a good kid. ... They were just over here a few days ago. They played with the puppy next door. He was a cute kid.

"This is just a tragedy for everybody. Poor Stephen. When I talked to my dad, I could hear him in the background crying that he had killed his brother and no one was going to like him anymore."

The Upper St. Clair School District Crisis Response Team has prepared plans to provide counseling and support to the Lanese family, students and school staff.

Funeral arrangements are being handled by the Frank F. DeBor Funeral Home in Brookline.