Yahoo TV

Four people were wounded and one has died after an elderly man opened fire inside a Minneapolis-area health clinic on Tuesday -- law enforcement officials described the gunman as a disgruntled former patient.

Police believe he acted alone in the attack.

Sheriff Sean Deringer: “I will identify the suspect as 67-year-old Gregory Paul Ulrich of Buffalo, MN…We believe Ulrich did act alone. We're not looking for any more suspects.”

Ulrich was taken into custody after Tuesday’s violence, which included an explosion 30 minutes after the shooting.

That's according to local media reports citing emergency dispatch audio.

Authorities told reporters that they weren’t able to confirm the reports of an explosion and that there was no reason to believe it was a terrorist attack.

Ulrich had been well known to authorities, receiving complaints as far back as 2003.

Buffalo’s Chief of Police said the attack was most likely related to an unspecified past "conflict" between the suspect and local healthcare providers.

Ulrich was scheduled to appear for arraignment related to that case on Thursday.

Sheriff Deringer said bomb squad investigators were called to the scene to examine a suspicious package found in the corner of the clinic’s lobby and additional devices found at a nearby motel where Ulrich had been staying.

The five people wounded in the attack were taken to hospitals, but it’s not known whether the victims were clinic patients or staff.

One later died, according to the county’s medical spokeswoman.