One person was killed and two others were hurt when a man opened fire inside of a local bar early Monday morning.
Police said the shooting happened at the Fort Pitt Inn off of Steubenveille Pike in North Fayette around 1 a.m.
Investigators identified the gunman as David Mazzocco, 25, of Imperial. According to police he appeared to become agitated with someone he was communicating with through text messaging and left the bar.
Police said Mazzocco then returned with three weapons. Officers said Mazzocco ordered two people inside of the bar to leave and then began shooting at the remaining patrons.
Investigators said two of those people were shot in the head. One of them later died at the hospital. Police identified the victim as James Adams, 29, of Imperial.
The other victim is listed in critical condition.
Police said a man sitting at a video poker machine tackled the gunman and disarmed him. He was also shot, but is expected to be OK. Officers said another patron inside of the bar held the gunman until police arrived.
"The two men who intervened need to be applauded for what they did. It was very courageous," said Allegheny County police Lt. Andrew Schurman.
Police said a motive was not immediately clear, though it appears that Mazzocco was having relationship problems and was in the middle of an argument when he began shooting.
In addition to the three guns police said he brought into the bar, an AR-15 assault-style weapon was found in Mazzocco's truck.
Investigators also said that Mazzocco is not permitted to own or carry firearms.
None of the firearms he used in the shooting were registered to him, police said. Investigators said they are actively looking for the owners of the guns and are working to determine how Mazzocco obtained them.
Mazzocco will be charged with homicide, attempted homicide, aggravated assault, recklessly endangering other people and weapons violations.