On school mornings, Shirley Parrish would watch the man who wanted to be her son-in-law as he buckled her grandchildren into their car seats.

Parrish and Stewart Edward Pelfrey would drop off the two boys at school. Then, they'd drink coffee together.

Pelfrey treated the children as if they were his own. He planned to marry Parrish's daughter, who was expecting their first child together later this year.

But their morning ritual and their plans for the future were disrupted early Friday when a man with a knife stabbed Pelfrey, 30, and two other men who were visiting the couple's home in North Charleston. As Pelfrey's two would-be stepsons slept, he collapsed in the street in front of their home and died.

"He was so happy to be having a new baby," Parrish, 63, said. "He won't get to meet his child because somebody decided to stab people at random."

But investigators don't think the man's actions were random. They were taking a close look at whether the man had acted under South Carolina's Protection of Persons and Property Act, a law that allows people to use deadly force if they fear imminent harm.

Pelfrey's family said he had died trying to break up a domestic squabble between the man and his former girlfriend.

But the North Charleston Police Department's probe indicated that Pelfrey and two others had dragged the man from his car, where he had been talking to the woman. The man grabbed a knife from his car and stabbed and cut the three.

Detectives later questioned the man, whom they did not publicly identify or charge. The state law calls for the police to examine a self-defense argument before making an arrest.

The two surviving men were taken to Medical University Hospital, where they were treated for cuts and later released, police spokesman Spencer Pryor said.

The ordeal unfolded about 2:30 a.m. at a mobile home at 281 Deidrich Road. Pelfrey and his girlfriend, Kayley Parrish, lived there with her two sons. Their neighborhood, the Dorchester Village Mobile Home Park, is just south of Charleston International Airport and west of Dorchester Road.

The couple had invited some friends and relatives to share a few drinks and "chill out," Shirley Parrish said.

What sparked the ensuing dispute wasn't clear, but family members said a man came to the home to confront his ex-girlfriend, who was a guest there. Outside, they started loudly arguing in a car parked on the street.

Pelfrey went outside to temper the argument, the relatives said, before the man came at him with a knife.

Many of the people there didn't know the man, they added. He had not been invited to the gathering, they said.

But the police said the trio's approach was more aggressive.

"The men opened the door and began to assault the alleged suspect," Pryor said in a statement. "He was then dragged ... to the roadway, where he began to utilize a knife that he retrieved from his vehicle."

Screams awoke Parrish. She lives two homes down the street.

After Parrish walked outside and stepped into the street.

"The man blew right by me," she said. "But I didn't know he was slashing people up."

Parrish found Pelfrey, who had become a son to her, lying on the pavement. Loved ones rushed to Pelfrey's side, but by the time authorities arrived, he was dead.

Police officers found the two wounded men lying on the front porch that overlooks marshland along the Ashley River.

The suspect was soon handcuffed elsewhere, the police said.

Pelfrey's arrest history contains convictions for only traffic and property crimes, the latest of which came when he was in his teens more than 10 years ago.

His death marked the seventh homicide reported this year in North Charleston. By this time in 2013, four people had been slain in the city.

As Parrish stood over the spot where he had died, she thought of what could have been, what should have been.

An electrician with a knack for remodeling houses and gardening, Pelfrey had become an "all-American dad" to her grandchildren, she said. He already had a child of his own.

He took them to parades and Charleston RiverDogs baseball games. They posed for a family photograph together. To Parrish, the picture showed that they all were happy.

Jay Hanckel, the father of Pelfrey's girlfriend, said he had recently met Pelfrey and planned to host a cookout this weekend for the new family at his West Ashley home.

"He treated her good and loved all those kids," Hanckel, 54, said. "I could tell he was a good guy and made (my daughter) happy. They were a real family."

Pelfrey's girlfriend had been pregnant for five months. They were looking forward to learning next week whether they would be having a boy or a girl.

She spent most of Friday morning crying.

Parrish remembered losing her own son in a car crash caused by a drunken driver, and she cried, too.

"When (Pelfrey) came along, he made it easier for me," she said. "You always lose the good ones."

Reach Andrew Knapp at 937-5414 or twitter.com/offlede.