"This is pretty scary," he said. "I may be packing heat for a while."
Local law enforcement officials decried the shooting as an attack on the criminal justice system.
"We understand that we may come into contact with violent people, but this is the next level," Kaufman County Sheriff David Byrnes said at a news conference.
Hasse, who previously worked as an assistant prosecutor in Dallas County, had worked in Kaufman County for three years. McLelland said Hasse worked hard and took work home with him at night and on weekends. He called him the office "storyteller."
Investigators gathered in a parking lot adjacent to the annex where the prosecutor was shot. Yellow tape and law enforcement vehicles blocked the area from spectators. Aulbaugh said a $20,000 reward was being offered.
"It's going to take a long time to get over this," said Wayne Gent, an attorney whose law office is on the courthouse square. "And the thing is — everybody's vulnerable."
Gent said he had a security system installed at the courthouse when he served as Kaufman County judge but that no system could prevent a shooting that occurs outside.
"How do you protect against that?" he asked.
Carolyn Mikeal, who works at an insurance agency on the square, said the shooting is a stunning development for the usually quiet community.
"It's just a shock," she said. "A small county like this — it's the last thing you expect to happen."