Winkler said Monday there have been many different statements from many different people about how exactly the chemical got into the sugar and then remained there for a month. The substance was mixed into the iced tea dispenser Aug. 10. Customer Jan Harding, 67, drank the tea and suffered critical burns to her mouth and esophagus. Her attorney has said she is improving and is regaining her ability to speak.
The cleaning product, used to remove grease from fryers, contains sodium hydroxide, or lye the active ingredient in drain cleaner.
Police will make no arrests unless Gill decides to file charges, Winkler said.
"Because of the severity of the ... injuries, we want to make sure our investigation was reviewed by a third party to make sure we've covered everything" before arrests are made, Winkler said. Detectives have asked prosecutors to consider a charge of reckless endangerment, but Winkler would not identify suspects, saying the investigators reviewed all employees, current and past, who were connected to the lye or tea.
Gill said he couldn't speak about the case, other than to say his office will carefully review the findings.
Dickey's Barbecue Restaurants Inc. said in a statement late Friday that it was an isolated incident and nothing like it had happened in the 73 years the Dallas-based chain has operated.
The South Jordan eatery remains open after county health officials inspected it and found all chemicals properly labeled and separated from food items.
The Associated Press contributed to this article.