Robert Rigg


Drake University law professor

Probable cause existed for deputies to investigate a possible driving-while-intoxicated charge against Assistant Jackson County Attorney Amanda Lassance, according to Drake University law professor Robert Rigg.

Rigg, an expert in criminal law and forensic sciences, said Clinton County sheriff’s deputies had enough probable cause to have administered sobriety tests based on a call Nick Shannon, who said he was Lassance’s boyfriend and was with her at the time, made to the Jackson County dispatch center at 12:56 a.m. April 6.

During the call and in body-camera footage the Sentinel-Press viewed as part of an open records request to the Jackson County Sheriff’s Office April 18, Shannon told deputies that he and Lassance were drinking and that he was holding a beer on the side of U.S. Highway 61 in northern Clinton County, where he and Lassance were stopped alongside the road.

If all the known circumstances lead a “reasonable and prudent person, in this case, the officer to believe that a crime has been committed or is being committed and that the defendant committed or is committing it, then you have probable cause,” Rigg said.

Rigg, who also is a criminal defense attorney, said the statements Shannon made to dispatchers and what deputies witnessed at the scene were enough to establish probable cause for an investigation, including sobriety tests.

 “[Deputies] certainly had enough probable cause,” Rigg said. “There certainly was reasonable suspicion” for Clinton County deputies to administer a breathalyzer and field sobriety tests “and probably to make an arrest for driving under the influence.”

However, Clinton County deputies Andy Petersen and Mark Mahmens Jr., who responded to the call, did not conduct sobriety tests at the scene, according to Clinton County Sheriff Rick Lincoln. Two weeks ago, Lincoln told the Sentinel-Press he “can’t answer why they didn’t do it” but said he had “full faith my deputies were acting in full accordance of what they believe they could do to make a case, so they must have had reason to believe they didn’t.”

Petersen wrote in his police report that there were beer cans in the car and that it smelled like alcohol.

There were also beer cans littering the ground next to the car, the report said.

Petersen wrote in his police report that he intended to conduct a sobriety test until Lassance told him she had been drinking in the car while it was stopped.

“From my training,” Petersen wrote in his report, “I know I wouldn’t be able to charge Amanda with OWI, as she admitted to consuming additional alcohol after operating the vehicle,” he said.

Rigg said the situational details at the scene should have strengthened the deputy’s reasons to investigate further.

“It gives me even more basis to trigger field sobriety tests,” Rigg said. “The fact that the inside was soaked in beer, and the fact that they were parked alongside a public highway, and the individual [Shannon] admitted drinking, that’s probable cause.”

Petersen cited Lassance and Shannon with violations for having open containers of alcohol in a motor vehicle. No other charges have been filed against Shannon or Lassance.

Rigg also said this is the kind of case that could be investigated by the Iowa Attorney General’s Office to ensure objectivity.