The man police said targeted a father and son in a Dallas office building earlier in the week has died, Dallas police said.
Robert Mustard, 60, died Wednesday after being admitted to Baylor Medical Center in Dallas with a self-inflicted gunshot wound. Police believe Mustard shot himself after first shooting Richard Smith and his son Chris on Monday morning.
Mustard is believed to be a past client of the Smith's, who run a financial services company.
Richard Smith was shot four times in the legs, and his son was shot in the neck and head. Both victims were transported to Parkland Hospital in Dallas and were in stable condition Tuesday.
Since Mustard has died, Dallas police said they will not file any charges.
Clayton Mitchell, a longtime neighbor of Mustard's, said he was surprised by the shooting.
"He seemed like a nice guy," he said. "There didn't seem like any type of violence to him."
Mitchell said he has lived across from Mustard for years at an apartment complex near LBJ Freeway and Midway Road in North Dallas. He said he had just spoken to Mustard on Sunday.
”He kept to himself," Mitchell said. "You didn’t see him other than at the store or walking through here (the apartment complex)."
Clerks at a nearby convenience store said Mustard is a regular customer. They recalled seeing him as recently as Sunday night.
“Something must have ticked him off for him to go to this point,” Mitchell said.
According to Dallas County court records, Mustard, who was a Dallas city attorney in the 1980s, spent nine months in Texas state prison for bribing a public servant in 1985.
NBC DFW's Ellen Goldberg and Grant Stinchfield contributed to this report.