FLUSHING, MI -- Pneumonia deaths in Flint rose 400 percent during the city's water crisis, special prosecutor Todd Flood contended Monday, May 21, during what may have been the last day of testimony in the preliminary examination of Nick Lyon, director of Michigan's Department of Health and Human Services.

Flood introduced hundreds of pages of death certificates in Genesee District Court during the cross-examination of a witness called by Lyon's attorneys, but public health officials said they could not immediately confirm the claim, and attorneys for Lyon suggested death certificates included victims who lived outside Flint.

Legionnaires' disease is a severe form of pneumonia, and experts have already testified in the Lyon case and at other preliminary exams that there were outbreaks of it during the 17 months that the Flint River was used as Flint's water source.

MLive-The Flint Journal could not immediately reach the Genesee County Health Department for comment on Flood's claim, and a spokeswoman for DHHS said pneumonia data collected by the state is not broken down based on city boundaries.

Bridge Magazine previously reported that the death toll from pneumonia nearly doubled in Genesee County at the height of the water crisis, supporting the suspicion among some experts that many of those deaths were actually undiagnosed cases of Legionnaires'.

DHHS officials have previously said there were 87 cases of Legionnaires in the county from April 2014 until October 2015 and that 12 deaths could be attributed to the disease during that same time.

Lyon is charged with involuntary manslaughter and misconduct in office. Special prosecutors claim the director deliberately failed to inform the public of the outbreaks, which resulted in the deaths of Robert Skidmore and John Snyder.

They allege Lyon participated in covering up the source of the county's Legionnaires' surges by attempting to prevent an independent researcher from looking into the cause of the outbreak.

Lyon, through his attorneys, has denied criminal wrongdoing and presented his own expert witnesses, including doctors who have testified that Skidmore and Snyder likely died from other causes.

They claim notes from a September 2015 conference call prove their client put the office of Gov. Rick Snyder on notice about outbreaks of Legionnaires' disease in Flint months before the governor eventually told the public in January 2016.

Gov. Snyder has said he only learned of the outbreaks and of suspicions they were connected to Flint water the day before his announcement.

Attorneys for Lyon did not formally rest their case during Monday's preliminary exam, which has been held so that Judge David Goggins can decide whether the director will be bound over on charges to Genesee Circuit Court for a jury trial.

But they said there probably will not be additional witnesses called and said the next step in the process will likely be a conference call to determine deadlines for filing written briefs with Goggins.

Oral arguments are also expected to be made before the judge makes his determination.

Monday's lone witness, Michael J. Reilly, a professor of clinical emergency medicine at New York Medical College and adjunct assistant professor at Columbia University, told Goggins the decision when to notify the public about Legionnaires' surges in the county is a matter of professional judgment by health officials.

Chip Chamberlain, an attorney for Lyon, said Monday that the law doesn't provide clear guidelines on notification and reviewed emails with Reilly that showed there were different theories about whether the outbreaks were caused by Flint water or were centered on McLaren-Flint hospital.

DHHS officials have said McLaren was home to the "largest healthcare-

associated Legionnaires' outbreak known in the U.S."

"People like Mr. Lyon don't have concrete guidance" on public notifications under those circumstances, Chamberlain said.

Reilly testified earlier Monday that the public needed to be told of public health threats in the "most timely manner as possible."

Emails from DHHS officials have shown the department was aware of the Legionnaires' outbreaks and suspicions they were tied to Flint water by October 2014.

The focus of the investigation later shifted to McLaren, according to other state emails.