A painter said to have carried out the North Carolina nursing home shootings may have been after his recently-estranged wife during the rampage that killed seven residents and a nurse.

A former security guard wanted for murdering five people in a shooting spree over the weekend killed himself today during a shoot-out with US police.

A suspended California security guard killed three co-workers and a fourth man, stopping during the rampage to call in threats to other employees at his former company, police said.

A one-time security guard who was suspended from his job last week shot and killed four people believed to be former co-workers.