Lovett Williams feared something was terribly amiss when he didn't see his 11-year-old twin grandsons outside their Penn Hills house after school yesterday afternoon.

"I knew something was wrong, because they usually get home at 3:30 and they come get me," said Mr. Williams, who lives across the street on Richey Drive from his grandchildren.

"So I went to the house and I used my keys to open the door. There was blood everywhere. Everywhere. Blood all over the house. Downstairs, up the steps."

A few minutes later, he found one of the twins, Tyrel, crouching in the attic, wrapped in a bloody blanket, complaining that his chest and stomach hurt.

He didn't notice at first, but underneath Tyrel was his twin brother, Tyron.

Tyron was pronounced dead at the scene. Tyrel was taken to Children's Hospital, where police said he was in satisfactory condition.

Last night, police were looking for the twins' older brother, Troy Hill Jr., 18, in connection with the stabbings. They offered no reason or motive for the stabbings.

Allegheny County Police Assistant Superintendent James Morton said residents in the area of Hulton Road had been advised to stay inside their homes while searchers used thermal imaging cameras and dogs in an attempt to find Mr. Hill in nearby woods. That search, however, was fruitless, and police said they believed Mr. Hill had left the area.

As the search for Mr. Hill went on, Mr. Williams recounted the gruesome discovery, his shirt stained with the blood of his grandchildren.

He said that after finding blood inside the house, he began screaming for the boys.

"Tyrel, Tyrel, where are you?," he said he called out. "He says, 'I'm up here Pappy.'

"I run up the steps and look in the bathrooms. They're all full of blood. The rugs are full of blood. And I say, 'I don't see you.'

"He says, 'I'm in the attic.' "

The attic is accessed by stairs that pull down from the ceiling. Going up the steps, Mr. Williams said he found Tyrel wrapped in a blanket.

"He says, 'Pappy, I'm dead,' " Mr. Williams said.

"I said, 'You're not going to die.' "

Mr. Williams asked his grandson where his twin brother was. He said Tyrel told him that Tyron was in a shed, behind the house. But Tyrel was apparently confused. Tyron was also in the attic, underneath Tyrel.

"I said, 'Who did this?' He said, 'Troy.' "

About that time, Mr. Williams said, the boys' mother, Tiffany Hill, called him on his cell phone, concerned that she hadn't been able to reach the boys. Mr. Williams told her to call 911.

"I was a little bit on the hysterical side. I was so upset," he said.

Mr. Williams said five patrol cars responded to the home in a matter of minutes. But he said an ambulance did not arrive until much later.

"I think they went to the Richey Drive off of Leechburg Road," Mr. Williams said. "I told them it was the Richey Drive off of Hulton Road. I'm talking to [the dispatcher] and the baby's lying here dying."

Mrs. Hill rushed home from work and arrived as medical personnel tried to revive Tyron, but were unable to save him.

Mr. Williams said his stepdaughter told him, "He's dead. They took all the equipment off him. He's dead."

The boys, who would mark their 12th birthday in November, were both straight-A students at Linton Middle School, youth league all-stars in baseball, and played football with the Guyasuta Football League. Tyron played quarterback and Tyrel was the running back.

A neighbor who did not want to give her name said she knew the family, which also includes the father, Troy Hill Sr., and a 3-year-old daughter, Tory. The child was not at home when the attack occurred.

"Those boys just mowed my grass last night," the neighbor said. "They were fabulous. The sweetest family, kind and caring people. And the boys were just the sweetest kids I've ever known."

Troy Jr. was a graduate of Penn Hills High School and attended Waynesburg College for one year, where he played football, his grandfather said.

As to what might have prompted the stabbings, the grandfather said: "He has a problem. He never would have done this to his brothers if he didn't have a problem."

He would not elaborate and said he could not imagine talking to the Troy Jr.

"I wouldn't know what to say to him," he said.

Superintendent Morton said Tyrel's wounds did not appear to be life-threatening. "We're talking with the parents and the younger boy."

He said the weapon that was used in the attack was not found at the scene. As a result, Superintendent Morton said, Mr. Hill was considered armed and dangerous.