Following a grand jury’s indictment of Gov. Rick Perry on charges of coercion and abuse of power, supporters of the state’s longest-serving governor have flocked to his defense, claiming he's the victim of a partisan witch hunt.

But Perry’s detractors are quick to note what the integrity unit was up to at the time — investigating allegations of improper reviews and conflicts of interest inside the Cancer Prevention and Research Institute of Texas, a grant-making entity that Perry has touted as one of his signature accomplishments. That inquiry, which resulted in an indictment of a high-ranking CPRIT official, was delayed by Perry's line-item veto of the unit's funding.

The public won’t know the details of Perry’s prosecution unless it goes to trial; be assured Perry's lawyers will try every legal tool in the toolbox to derail it. In the meantime, the secrecy surrounding the evidence the grand jury heard is providing fertile ground for speculation.

Perry and his lawyers say the governor was simply exercising a constitutional right when he vetoed $7.5 million in state funding for the public integrity unit, which is overseen by a district attorney who had pleaded guilty to drunken driving.

“This is nothing more than banana republic politics," said Houston lawyer Tony Buzbee, who is leading Perry’s legal team. “What has happened here not only has no merit, but also was absolutely contrary to the law.”

The leading theory Texas Democrats are peddling is that Perry wanted to upend the public integrity unit, which is housed within the Travis County’s district attorney’s office, because it was investigating CPRIT — bringing at least one of Perry’s major donors under the microscope.

Mo Elleithee, a spokesman for the Democratic National Committee, insinuated in an email to supporters that Perry might be "using a veto in attempt to force an elected official to resign and possibly stymie a politically damaging investigation."

CPRIT, an entity created by voters in 2007 to spend $3 billion on cancer research, came under investigation after an oversight committee disclosed that the agency had approved an $11 million grant to Peloton Therapeutics without scientific review.

One of Peloton’s initial investors was Dallas philanthropist Peter O’Donnell, a friend to Perry who has donated $241,000 to his campaigns since 2000, campaign finance records show. At the time, The Dallas Morning News reported that O’Donnell had also given $1.6 million to the CPRIT Foundation, a nonprofit. State law prohibits the CPRIT Foundation from accepting donations from CPRIT grant recipients.

The public integrity unit eventually indicted Jerry Cobbs, CPRIT’s former chief commercialization officer, for allegedly deceiving CPRIT officials about the grant given to Peloton Therapeutics. At the time, Travis County District Attorney Rosemary Lehmberg said, "other current CPRIT board members are not under suspicion in the investigation."

In the months preceding and following Perry's veto, the public integrity unit certainly had more on its plate than CPRIT. It was pursuing more than 400 cases at the time of the veto, including 23 “public corruption” cases, county documents show.

Of those public corruption cases, 10 resulted in indictments, including an elected sheriff who had allegedly falsified records and various state employees who had been accused of behaving unscrupulously. Another 13 public corruption cases remained under investigation and were therefore confidential.

While details on what the grand jury heard are thin, it's indisputable that the public integrity unit took a hard hit from the veto. While Travis County covered some of the lost funding, the unit’s annual operating budget dropped to $2.5 million from $3.7 million. The unit was forced to downsize to 24 employees from 34, and it reportedly dropped more than 50 of its pending cases — none of which fell under the “public corruption” category.

Disclosure: Tony Buzbee was a major donor to The Texas Tribune in 2012. A complete list of Texas Tribune donors and sponsors can be viewed here.