First, the police stopped the vehicle on the basis of an anonymous tip which did not present any information that the vehicle was being driven in a manner, where there was probable cause to suspect the driver was driving under influence of alcohol.
Rock Valley businessman Leon Kooima was driving the SUV occupied by five of his friends and business associates. They were returning after a charity golf in Okoboji, and stopped at a restaurant on their way home. The tipster phoned when they left the restaurant.
The grudges of the anonymous tipster, Craig Post, as recorded in court documents were the vehicle “is full of drunks” who are “huge money guys.” And “What bothers me is these guys get away with everything, ‘cuz they know everybody in Rock Valley and they think they can do everything.”
Secondly, the police followed the SUV and asked it to stop despite absence of any erratic driving, any traffic violation, or any similar problem that could have provided probable cause to stop the vehicle.
After the police conducted a breath test, Kooima failed the blood alocohol level limits. He was immediately arrested, charged with DUI and convicted.
Kooima appealed arguing the police made the vehicle stop unlawfully, and his rights under the 4th Amendment of the U.S. Constitution had been violated by the unlawful search and seizure.
The Iowa Supreme Court agreed, overturned the conviction, and stated that any evidence obtained by unlawfully stopping the vehicle (including results of the breath test and the field sobriety test) cannot be admitted as evidence if a new trial is held.
In the instant case there was lack of probable cause to stop the vehicle and conduct the tests, because neither was Kooima driving in a manner to suspect drunken driving, nor did the information given by the anonymous tipster relate to drunken driving.
So, stopping the vehicle and the following breath and field sobriety test was done unlawfully.
The court also made it clear that dispatchers should obtain sufficient information from anonymous tipsters about illegal activity to support probable cause for warrantless search and seizure. Otherwise police would be free to stop anyone on anonymous tips based on intentions to harass or based on rumors or a personal suspicion without evidence.