US prosecutor quits Aryan Brotherhood case for 'security concerns' Investigators have disclosed no evidence that ties the white supremacist gang to the murdered prosecutors and Mr Hileman did not elaborate on the "security concerns" in his brief email. But several Texas prosecutors have expressed fear for their safety and their families following the targetted killings of Mr McLelland, mown down with his wife in their home at the weekend, and Mr Hasse, shot dead in a car park near the Kaufman courthouse two months earlier. Texas and federal investigators have been interviewing jailed Aryan Brotherhood members and poring over the past cases prosecuted by the two dead men as they seek a suspect and motive for the murders. Amid speculation in the town that they could have been killed as a result of a local vendetta, the lawyer of former county justice of the peace prosecuted for theft by the two men said that his client had voluntarily submitted to gunpowder residue tests after each killing. Both tests on Eric Williams were negative, according to his lawyer David Sergi. He said that Mr Williams, who was sentenced to two years' probation and a $2,500 fine last year for stealing office computer monitors, had just learned that a tribunal would hear his appeal. Officials are also understood to be looking into a rant on the Facebook social media site, purportedly posted by a Kaufman resident, claiming that the killings were "revenge against the tyrannical, unjust, Pit Bull style treatment of every poor soul damned to do business in the ... courthouse."