The Kaufman County Courthouse remained closed Friday as investigators continued their search for clues in the wake of a brazen fatal shooting of a prosecutor just outside the building a day earlier, officials said.

During a Friday morning briefing, officials of North Texas law enforcement agencies said they were working through leads in the shooting death, which targeted the Dallas-area prosecutor as he headed to work Thursday.

Kaufman Police Chief Chris Aulbaugh said investigators had made no arrests in connection with the shooting of Kaufman County Asst. Dist. Atty. Mark Hasse, 57....

The shooting came the same day U.S. Department of Justice officials publicly thanked Hasse for his help in prosecuting members of the Aryan Brotherhood of Texas, but Aulbaugh said investigators have yet to link that case to the shooting.

"We're not ruling out any involvement until we know. We have no specific information that Aryan Brotherhood is a factor here," the police chief said during the briefing. "It seems to be coincidence that this release from DOJ had to do with that case."

He said Hasse had not worked any other recent cases involving the Aryan Brotherhood....

Witnesses have described two suspects who approached Hasse in the courthouse parking lot that morning as dressed in black, wearing masks and tactical vests. They reportedly fled in a brown or silver sedan, possibly a Ford Taurus, but Aulbaugh said there was no additional information available Friday....

He said a Crimestoppers reward for information about the suspects, boosted by a match from the Dallas district attorney’s office Friday, had almost doubled since the day before to $64,500.

"We encourage anyone who may have seen something, call it in to our tip line -- we will follow every lead we receive," Aulbaugh said.

Kaufman County Criminal Dist. Atty. Mike McLelland said the courthouse, placed on lockdown after the shooting, is expected to reopen in a few days.

"This is new territory for everybody," he said.