Police have arrested an Idaho prison inmate and the accomplice who helped him escape with investigators looking into whether they killed two people while on the run.
Two white supremacist gang members were arrested on Thursday following an attack on corrections officers at a Boise hospital.
Skylar Meade, the escaped inmate, and Nicholas Umphenour, the man who police say shot two Idaho corrections officers early on Wednesday to break Meade out of custody, were arrested after a brief car chase on Thursday afternoon in Twin Falls, about 130 miles from the hospital.
Authorities said they were investigating two homicides, in Clearwater County and Nez Perce County, which borders Washington state.
Both victims were men. Police found shackles at the scene of one of the killings and "that's one of the ways we tied them together," Idaho State Police Lt. Colonel Sheldon Kelley said.
Meade, 31, was sentenced to 20 years in prison in 2017 for shooting at a sheriff's sergeant during a high-speed chase.
Umphenour was released from the same prison — the Idaho Maximum Security Institution in Kuna, south of Boise — in January.
The two had at times been housed together, were both members of the Aryan Knights prison gang, and had mutual friends in and out of prison, officials said.
No shots were fired during the arrest, police said.
The attack on the Idaho officers came just after 2am on Wednesday in the ambulance bay of Saint Alphonsus Regional Medical Centre, as they were preparing to return Meade to the prison.
He had been brought to the hospital earlier in the night because he injured himself, officials said.
After the ambush, one officer shot by Umphenour was in critical but stable condition while the second wounded officer had serious but non-life-threatening injuries.
A third corrections officer also sustained non-life-threatening injuries when a responding police officer — mistakenly believing the shooter was still in the emergency room and seeing an armed person near the entrance — opened fire.
Correction Director Josh Tewalt said a guard had been released from the hospital, and the other two are stable and improving.
The department is reviewing its policies and practices in light of the escape, he said.
The Aryan Knights is a gang that formed in the mid-1990s in Idaho's prison system to organise criminal activity for a select group of white people in custody as well as outside prison walls, according to the US attorney's office in the district of Idaho.
Recently, Meade had been held in a type of solitary confinement called administrative segregation because officials deemed him a severe security risk, Mr Tewalt said.
He had been escorted in the ambulance and at the hospital by a uniformed, unarmed officer wearing a ballistic vest, tailed by two armed officers, Correction officials said.
Security for transporting Meade to the hospital from prison was enhanced because of his violent history, but the department will review their overall policies for transporting inmates to hospitals, Mr Tewalt added.
