Thomas' fellow inmates told Detective Kyle Mrozinski of the Milwaukee Police Department, which is investigating the 38-year-old's death, that they recall Thomas begging jail guards for water repeatedly.
Inmate Marcus Berry said that "starting on Monday and every day after that, Thomas asked every (correctional officer) for water because the water in his cell was shut off," Mrozinski testified.
Thomas died April 24, 2016, and exactly one year later prosecutors launched an inquest to determine if anyone is criminally responsible for his death. Three other people, including a newborn, have died in the Milwaukee County Jail since Thomas' April 2016 death.
The Milwaukee County Medical Examiner's Office ruled Thomas' death a homicide in September, leading to more questions about what happened and why.
Prosecutors say that after being denied water for a week, Thomas died of dehydration in his Milwaukee County Jail cell. Testimony is slated to continue Monday in the inquest.
No one knew?
"It should have been the toilet water, just the toilet water," Lt. Kashka Meadors of the Milwaukee County Sheriff's Office said Thursday. "I instructed to have the toilet water cut off because he was flooding the toilet."
"No one informed me that his water was off," Officer Thomas Laine testified.
Meadors said that part of the confusion stemmed from no one logging the decision to turn off Thomas' water.
"It ought to be noted, but it is not noted in the logs like it should be, probably because it happens so often," she testified.
More testimony this week
Thomas' family has filed a 25-page civil complaint against Sheriff David Clarke, who oversees the jail, Milwaukee County and other jail officials. Among the allegations in the lawsuit is that the defendants deliberately and willfully failed to provide Thomas medical care.
The Milwaukee County Sheriff's Office has not returned CNN's request to comment and has been largely silent on Thomas' death.
Thomas was arrested on April 15, 2016 and charged with reckless endangerment and felony firearms violations after he fired shots in a local casino, according to court documents and WITI. All charges related to his arrest were dismissed after his death.
The inquest continues Monday as the prosecutor's office continues to call witnesses before a jury of six people. After witnesses testify and all evidence is presented, the jury will determine whether there are adequate grounds to file criminal charges, and then make a recommendation.
Prosecutors are not obligated to follow the jury's recommendation.