When several men broke into a Waxahachie truck terminal last October, tied up a security guard at gun point and crashed a semi-trailer loaded with $1 million in cigarettes through the front gate, they didn’t know one of them was a snitch for the Dallas County Sheriff’s Department.



A sheriff’s detective who was in contact with the informant that night said he didn’t know the crime would turn into an armed robbery. But the informant was surprised to be arrested months later, saying the detective knew for weeks what he was planning.



The Sheriff’s Department launched an internal investigation of its auto theft task force after local police officers complained that the detective hid key information from them to protect his informant.



That investigation cleared task force officers of any wrongdoing, but it exposed what critics called sloppy procedures by the sheriff’s department and lack of controls over the use of informants. ...



Task force detectives knew days in advance that the truck heist was going down at the Celadon trucking terminal in Waxahachie. They did not intervene and, in fact, weren’t even at the scene. The plan was to find out where the stolen cargo was headed. But it was thwarted when Dallas police were alerted to the abandoned truck.

Sheriff Lupe Valdez said she hadn’t read the 10-page report, which she called a special assignment and not an investigation. Nevertheless, she said she was satisfied with the task force’s performance based on the staff briefing she received and doesn’t see the need for any changes.



“The informant did what he had to do,” she said, referring to the informant’s participation in the heist.



Sheriff Valdez said she plans to read the report when she has time but doesn’t want to micromanage her departments.



“I have good officers who do their job. They inform me of what’s going on,” she said.



Sheriff Valdez said she plans to read the report when she has time but doesn’t want to micromanage her departments.

Ellis County District Attorney Joe Grubbs said officers cannot have an agreement to permit someone to break the law.



“The danger in having a crime like that is that you don’t know how far it could go,” said Mr. Grubbs, whose office will handle prosecutions in the case.



Terri Moore, who is Dallas District Attorney Craig Watkins’ second in command, agreed that police cannot allow informants to commit crimes. “You’ve got to draw a line between you and a snitch somewhere,” she said, declining to comment specifically on the sheriff’s report. ...



In the Waxahachie case, the thieves had to drive the stolen truck past a manned security gate. Had the security guard been shot during the robbery, the Sheriff’s Department would have had some difficult questions to answer, experts say.



“When there is a known risk of harm to innocent victims, that crosses the line,” said Gerald F. Uelmen, a Santa Clara University law professor and former federal prosecutor. ...



“Very often, an informant is given a free pass to engage in criminal activity,” said Mr. Uelmen, who is also executive director of the California Commission on the Fair Administration of Justice, which has studied the use of jailhouse informants. “There needs to be tighter control over what informants are allowed to do.”

While clearing its own officers, the sheriff’s internal investigation blamed Det. Wallace, a member of DPD’s commercial auto theft unit, for the interdepartmental distrust. The report said he has interfered with task force investigations and told other police officers the task force had an improper relationship with Mr. Kelly.



The report concluded that there is an “element in the Dallas Police Department who is not beyond calling into question the trustworthiness” of the task force and the sheriff’s department in general.