BUFFALO, Minn. (AP) _ An investigator says dependence on opioid medication was the ``driving force'' behind last week's shooting at a Minnesota health clinic that left one person dead and four injured.

In an application for a search warrant, Wright County Deputy Patrick Bailey says authorities found a plastic bag containing six oxycodone pills in a search of Gregory Ulrich's hotel room.

Bailey also describes a video in which Ulrich mentions taking more than 30 pills at a time.

Ulrich is charged with murder, attempted murder and other counts in the Feb. 9 shooting at an Allina Health clinic in Buffalo.