LAS VEGAS (AP) — Nevada is back to planning stages after a judge postponed what would have been the first execution in 12 years.

The state was planning on using a never-before-tried combination of drugs for the lethal injection of convicted killer Scott Raymond Dozier.

Nevada announced last week it would substitute the sedative midazolam for expired prison stocks of diazepam, commonly known as Valium. That raised concerns among death penalty experts about whether Dozier would be unconscious enough not to react to pain.

Midazolam maker Alvogen filed a lawsuit accusing Nevada of illegally securing midazolam for unapproved purposes.

Nevada is required by law to use lethal injection for executions. The state is expected to appeal.

Dozier has said he wants to die rather than spend his life in prison.