Authorities said they can't find a motive for a drunken gunman who opened fire at a Pennsylvania hotel bar, killing two men and wounding a woman before breaking into a home where he fatally shot another man before killing himself.

State College police completed their investigation into the January shooting that happened a few miles away from Penn State's campus, Centre County District Attorney Bernie Cantorna said Wednesday.

Authorities said 21-year-old Jordan Witmer and friend Nicole Abrino, 22, spent what she called a "normal evening" at a pizzeria before going to P.J. Harrigan's Bar & Grill in State College, Centre Daily Times reported .

Police said Witmer went to the restroom and when he returned, Abrino heard the bartender "say something about a gun," Cantorna said. She told Witmer they should leave. That's when Witmer shot her once in the chest with a gun he was licensed to carry, Cantorna said.

He then turned the gun on Dean Beachy, 62, and his 19-year-old son, Steven. The two men, who family members said were in town from Ohio for a horse auction, died.

Witmer fled, crashed his car and shot his way into a random home, Cantorna said. He killed 82-year-old George McCormick before killing himself.

Cantorna said Witmer's blood alcohol content was about three times the legal limit.

He said there is no video of the shootings and no evidence the shootings were premeditated.

Abrino survived the shooting and a bullet remains lodged in her spine; doctors do not believe they can safely remove it. She said she saw no "red flags" during her time out with Witmer.