Before being moved into the general population at the Oxford County Jail, jail officials ensured accused killer Christian Nielsen would not pose a danger to himself. A suicide screening showed “no red flags,” the jail administrator said, and Nielsen, after 24 hours, was allowed to mingle with other inmates.

It seemed trusting for a man accused of butchering four people over the Labor Day weekend. Maybe too trusting.

On Friday, Nielsen allegedly attacked another inmate with a mop wringer and had to be tackled by a corrections officer.

Nielsen is now housed in the Cumberland County Jail, a facility better able to separate him from other prisoners.

Nielsen’s erratic behavior behind bars in Oxford County, though unpredictable, cannot be considered unexpected. He’s the lone suspect in the most grizzly slayings in recent Maine history, and he seems to have little to lose through continued aggression.

In hindsight, the overcrowded 27-bed, 27-year-old Oxford County Jail was the wrong place to house Nielsen, even for a single night. Officials should have placed him in a more secure facility from the beginning to ensure his safety, the safety of jail staff and the safety of other inmates.

Friday’s incident also highlights the challenges facing Maine’s county jails; aging facilities that are ill-equipped to meet the needs of our modern correctional system.

On Sept. 3, the Sun Journal reported the story of Daniel Jackson, a mentally-ill inmate in Franklin County, one of many inmates who require special services from county jails.

Oxford County Sheriff Lloyd “Skip” Herrick told us smaller jails are unable to provide these necessary services. “We are not equipped to deal with them,” Herrick said, of inmates with mental illnesses.

The same could be said about inmates charged with excessively violent crimes.

Instead of renovating older jails or building expensive new structures, however, perhaps Maine’s county jails should adopt more rigorous standards for handling inmates charged with capital crimes.

Though unprovoked attacks like Nielsen’s cannot be predicted, sound practices could contain future violence.

Androscoggin County, for example, first places inmates charged with capital crimes in maximum or high-maximum security, where their movement and interaction with other inmates is limited. Maximum security inmates are confined to cells, given just two one-hour periods to watch television, shower or use the telephone. A maximum-security cell block holds about four prisoners.

Jails have more responsibility than just protecting the public, said Capt. John Lebel, administrator of the Androscoggin facility. Jails must also protect the corrections officers who work inside the jail, said Lebel, and protect jail inmates from each other.

We agree.

Officials in Oxford County said Nielsen showed no red flags, yet the charges against him were clear red flags for violent and unexplainable tendencies. Nielsen is now where he should have been from the start.

The attack is also a warning to officers escorting Nielsen outside the jail, such as for further hearings and his inevitable trial. All precautions should be taken to deal with the suspect’s unpredictable behavior, if it manifests in public, from harming more innocent people.