A teacher admitted he fatally stabbed a couple he didn’t know who were hiking with two of their children in an Arkansas state park, US authorities said, after a five-day search and hundreds of tips led to his arrest.

State Police arrested 28-year-old Andrew James McGann on Wednesday at a barbershop in Springdale, approximately 50 kilometres north of Devil’s Den State Park, said Major Stacie Rhoads, commander of the department’s criminal investigation division.

McGann is charged with two counts of capital murder in the killing Saturday of Clinton David Brink, 43, and his 41-year-old wife Cristen Amanda Brink.

McGann is being held without bond.

“He did indicate that he committed the murders,” Rhoads said during a news conference.

When asked to elaborate, she said: “I would call it an admission.”

Arkansas State Police Colonel Mike Hagar said authorities are trying to determine a motive for the attack and have no reason to believe McGann knew the couple or their children.

Officials said the husband was stabbed first, approximately 800 metres into the park, then the mother ushered her children to safety before returning to help her husband.

She was also stabbed to death.

Authorities have not said if the girls witnessed both their parents being killed.

McGann was cooperative during the arrest and admitted to killing the couple soon after, Rhoads said.

Police also matched his DNA to blood found at the crime scene.

The case is distressing even to the police.

“In my 27 years that I’ve been with the State Police, this is probably one of the most heinous that we’ve had, especially the aspect of just how random it was,” Rhoads said.

But officials emphasised at the news conference that McGann, who has no criminal record, is innocent until proven guilty.

Washington County prosecutor Brandon Carter said he did not know if McGann has a lawyer or will need a public defender.

The Associated Press has left messages at a number listed for McGann.

Two of the Brinks’ three daughters — ages seven and nine — were with them on the hiking trail on Saturday, but they were not hurt and are being cared for by family members, authorities said.

Authorities said the investigation was set in motion when they reported the killings to another hiker on the trail.

The State Police collected photos and videos from other hikers who didn’t witness the attack but were on the trails at around the same time.

Police also released a composite sketch and a photo that showed a person of interest from behind.

The police then narrowed down the suspect’s vehicle, which had tape over the license plate, using surveillance footage from homes and businesses near Devil’s Den.

Within an hour of McGann being identified as a suspect, he was caught at the barber shop.

“Everyone speculates that there was a lot of thought that went into this to conceal his identity, but on the other side of that, he was very sloppy,” Rhoads said.

Carter indicated the state would give a jury the option to sentence McGann to the death penalty.

Suspect taught in other states before Arkansas job

McGann has active teaching licenses in Arkansas, Texas and Oklahoma, according to each respective government certification website.

There are no infractions or suspensions noted on his public state licensures in any of those states.

The Associated Press reached out to all three state education agencies on Thursday.

McGann was placed on administrative leave in spring 2023 while he was employed at Donald Elementary School in Flower Mound, Texas, “following concerns related to classroom management, professional judgment, and student favouritism,” according to a spokesperson for the Lewisville Independent School District.

Sierra Marcum, whose son was in McGann’s fourth-grade class, said the teacher came across as “pretty cold” and “disinterested in his students”.

Marcum said her son had come home from school upset about some of McGann’s behaviour, which she reported to the school’s principal.

McGann resigned from the Lewisville posting in May 2023, the district said in a statement.

He also taught at a small Oklahoma school district from the summer of 2024 until May this year.

He resigned to take a job in another state, according to a statement from Sand Springs Public Schools, near Tulsa.

The district said McGann passed all background checks.

Law enforcement hasn’t contacted Sand Springs Public Schools regarding the investigation, according to district spokesperson Lissa Chidester.

McGann had not yet started his new job in Arkansas at Springdale Public Schools, said Jared Cleveland, the district superintendent.

He said the district could not provide more information, citing the investigation.

The victims had just arrived in Arkansas

The Brinks had recently moved from South Dakota to the small city of Prairie Grove in northwest Arkansas.

Their water was connected less than two weeks ago, Mayor David Faulk said.

Clinton Brink was supposed to start working as a milk delivery driver on Monday in the Fayetteville area, according to Hiland Dairy, his employer.

Cristen Brink had been licensed as a nurse in Montana and South Dakota before moving to Arkansas.

The Brink family said the couple died “heroes protecting their little girls.”

Devil’s Den is a 2500-acre state park near West Fork, about 220 kilometres north-west of Little Rock, the state capital.

Its trails have been closed to the public since Saturday.

Officials on Thursday assured the public that there is not a pattern of violence at state parks.

“Someday they’re going to reopen Devil’s Den State Park and I’ll be on the trail once that happens,” Carter said.