DALLAS - Charges are still pending against a man suspected in the shootings of two men at a north Dallas financial services office.

Dallas police say 60-year-old Robert Randall Mustard remains in critical condition at Baylor University Medical Center on Tuesday with what they say is a self-inflicted gunshot wound. Dallas police Sr. Cpl. Gerardo Monreal says no charges have been filed.

Dallas police Sr. Cpl. Kevin Janse said Mustard walked into a financial services office on the third floor and opened fire on two men with whom he had been having an ongoing dispute. The nature of the dispute was not immediately clear. Police say Mustard shot 66-year-old Richard Smith and Smith's son, 39-year-old R. Chris Smith, before shooitng himself as police closed in.

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The father was shot in the legs, and his son was shot in the neck. Both are in serious condition at Parkland Memorial Hospital in Dallas on Tuesday.

The shootings happened about 10:30 a.m. Monday in the 15-story Four Forest office building near U.S. Highway 75 and Interstate 635.

Three Dallas police officers arrived on the third floor and heard a gunshot.

"Officers thought they were being shot at and were in fear for their lives, so one officer fired at the suspect but missed," Janse said. "Apparently, the shot that the officers heard was the suspect shooting himself."

Police say the shootings could have been much worse, but new training may have prevented greater tragedy. Last year, Dallas police started training all patrol officers in "rapid rescue" response. Officers are trained to handle "active shooter" scenarios in buildings and can enter quickly rather than wait for a SWAT team to arrive.

"There is no doubt that the quick response from the officers and the active shooter training prevented the suspect from killing the father," Janse said.