The man accused of stabbing three people, one of whom died, and of then killing a Sunset police officer with his own gun before barricading himself inside a convenience store was a cousin of the slain officer, officials said.

St. Landry Parish Sheriff Bobby Guidroz said the officer who was killed was Henry Nelson, 51. Also killed was Shameka Johnson, 40, Guidroz said. Two others were injured with stab wounds, including the suspect’s wife, the sheriff said.

He identified the suspect as Harrison Lee Riley Jr., 35, of Arnaudville, who Guidroz said late Wednesday was taken to a Lafayette hospital for treatment of tear gas inhalation.

Authorities planned to book him sometime into the parish jail Thursday on two counts of first-degree murder, Guidroz said.

Sunset Police Chief Luis Padilla said Riley and Nelson were cousins, but he was unsure of how close. Guidroz said Riley also was related to Johnson.

Such relations are not unusual in the rural St. Landry Parish community, Padilla said.

“We know everybody. This is a small town,” he said.

Shameka Johnson’s sister, Grand Coteau Mayor Shaterral Johnson, also confirmed Riley is her cousin and that family members told her he was on drugs when he went on the violent rampage outside her mother’s house on Anna Street.

She said another sister was also stabbed and was being treated in a Lafayette area hospital for her injuries.

Guidroz said Riley’s wife, Courtney Jolivette Riley, also was stabbed and required hospitalization.

Shameka Johnson and sister Surlay Johnson were at the Anna Street home Wednesday afternoon and tried to intervene when Riley arrived and began arguing with his wife, Guidroz said.

At some point, police were called, though it is unclear at this point by whom or how many people had been stabbed by the time the officer, Nelson, arrived.

“We were told he was responding to a stabbing. That was the last thing we heard on the radio,” Padilla said.

Riley took the officer’s weapon, then shot him, Guidroz said, but the investigators have yet to determine how or when that happened during the struggle.

He said Riley then fled about three blocks away to the mini mart and gas station, where he crashed his black Nissan Altima into the front of the market and holed up in the office there.

“It went to hell in a hand basket from there,” Guidroz said.

Tammy Adams, a cashier at the store, said she was working at the register when suddenly the car came crashing through the front of the store and glass shattered everywhere.

“He came around the counter, and I was just trying to get out,” said Adams, who managed to escape safely. “He was just on a rampage, I guess.”

Adams said she recognized the man as a customer but did not really know him.

“He just didn’t look like himself,” she said.

The SWAT team went in shortly before 6 p.m., using tear gas to try to get Riley out as they worked at the officer door with hammers and axes, Guidroz said.

Guidroz said three people were in the store when the suspect came in and all safely escaped. The suspect’s brother and a State Police negotiator were on the scene at one point trying to get the man to come out of the store.

Nelson was one of six officers on the small town police force, having served since 2002, Padilla said. He said the starting salary for a Sunset police officer is about $1,200 a month.

Nelson’s last day of work before a scheduled month-long vacation to visit a teenage daughter was to have been Thursday, Padilla said.

“Everybody in town loved him,” the police chief said

He described Nelson as “a big heavyset teddybear … When he arrested you he arrested you with a smile.”

Shaterral Johnson, the Grand Coteau mayor, said Riley didn’t live on Anna Street where the officer was shot and the others were stabbed.

“I have no idea why they came to our house, ” she said.

Next door neighbor Yvonne Malbrough, 69, whose home was still wrapped in crime tape, said she has known the Johnson girls since they were small.

“It’s heartbreaking...to see babies that then grow up to be women and then you come back home and see...(them) on the ground dead,” she said.

“This is a tight knit area right here. I tell you, the quietest area,” said neighbor Dwayne Malbrough, 47. “I’m gonna miss her,” he added, referring to Shameka Johnson.

Nelson is the sixth on-duty officer in Louisiana to have been shot and killed in Louisiana this year, more than in any year in the past decade, according to statistics compiled by The Advocate.

Funeral services are set this Saturday for State Police Trooper Steven Vincent, who was shot in the head Sunday by a man he was trying to help in Calcasieu Parish. Earlier this month, Shreveport Police Officer Thomas LaValley, a native of St. Amant, was gunned down while responding to a suspicious person call.

Advocate staff writers Maya Lau and Danielle Maddox contributed to this report.