Prosecutors said they are poised to file murder and other felony counts Thursday against Gregory Ulrich, the suspect in the Buffalo health clinic shooting Tuesday who allegedly killed a staff member and wounded four other employees.

Wright County Attorney Brian Lutes said he intends to charge Ulrich, 67, with second-degree intentional murder, four counts of attempted first-degree attempted murder, and possession of an explosive or incendiary device in connection with the shooting inside the Allina Health Clinic.

In the meantime, Ulrich remains jailed and could make his first court appearance Thursday, soon after the criminal complaint is filed.

In a rare move for prosecutors, Lutes not only spelled out the charges ahead of filing but also elaborated on his intentions, saying in a statement, "I will aggressively prosecute Ulrich for this horrible crime and the pain he caused to the victims, their families and the entire community."

Lutes said he met with local, state and federal law enforcement representatives "all morning" Wednesday in preparation for crafting the charges, which are expected to offer a detailed account of Ulrich's possible motive and his actions leading up to, during and immediately the shooting.

A man who roomed with Ulrich as recently as July told the Star Tribune that the alleged gunman had binged on painkillers and was irate at a doctor who would not prescribe more.

Ulrich, a longtime resident of Buffalo, had "multiple contacts" with law enforcement dating back to 2003, Police Chief Pat Budke said a few hours after the shooting, and had a history of being unhappy with health care he had received.

Family identified the person killed as 37-year-old Lindsay Overbay, a clinic medical assistant. She died at HCMC in Minneapolis hours after the shooting.

One victim is in critical condition, one is in fair condition and one is in good condition at North Memorial Health Hospital, officials there said. A fifth victim was treated at North Memorial and released.

Allina late Wednesday afternoon identified one of the wounded as Sherry Curtis, a licensed practical nurse. Allina did not specify the seriousness of her injuries. Three other clinic staff members remain to be identified.

Paul Walsh • 612-673-4482