Iowa must return $188,640 and a truck it seized because the state transportation officer who made the traffic stop has no legal authority to enforce speeding infractions, a judge has ruled.

It's the latest in a string of legal challenges alleging that Iowa Department of Transportation officers are writing tens of thousands of traffic tickets in violation of Iowa law and an attorney general's opinion that says the officers have limited enforcement powers.

In a ruling this month, Pottawattamie County District Court Judge Richard Davidson said that Iowa Department of Transportation Sgt. Kevin Killpack did not have the legal right to stop David Ellis Mansor Jr. on Jan. 11, 2016.

And, because there was no other probable cause for the stop, there are no grounds for the state's decision to confiscate Mansor's truck and the cash they found inside, Davidson ruled.

It's Iowa's first forfeiture case defeat based on the argument that a transportation employee overstepped his authority, violating a motorist's constitutional rights by making an illegal stop and seizing property.

"He stopped Mr. Mansor in a state-logoed vehicle and asserted his authority under his role as a peace officer for the DOT," Davidson wrote in his ruling. "To be sure, even if Sgt. Killpack had some authority to stop a vehicle as a concerned citizen, such a citizen does not have the right to search and ultimately seize private property."

DOT acting illegally?

Davidson's ruling builds upon a legal issue that began last year when Pleasant Hill resident Peyton Atzen and his family successfully challenged a speeding ticket that could have resulted in the teen's license being revoked.

Atzen's attorneys, Brandon Brown and Gina Messamer of the Parrish Kruidenier law firm, successfully argued the ticket was invalid because Iowa law restricts the enforcement powers of DOT officers.

The Iowa Supreme Court ruled nearly 70 years ago that DOT officers did not have the same powers as troopers.

A 1990 Iowa attorney general opinion concurred, saying DOT officers' authority, based on another section of the law, is limited to drunken driving enforcement and commercial motor vehicle violations related to registration, size and weight.

The Atzen ruing has led to a legal effort being pursued by Brown that, if successful, could force the state to refund millions of dollars in fines and remove the wrongful convictions from tens of thousands of motorists' records.

"We intend to hold them accountable for their past and continued illegitimate actions," Brown said Tuesday.

And, in at least one other case, a Warren County judge earlier this year dismissed another motorist's ticket based on the arguments made in the Atzen case.

The DOT maintains that the rulings were made in error and do not set precedent. They insist that the issue is one of public safety, noting their officers receive the same training as troopers.

The agency's officers continue to issue tickets to non-commercial vehicles. The agency also has pursued Senate File 473, a bill that would grant DOT officers the right to make such stops.

Despite the DOT's contention that its officers have acted legally, the agency does not plan to appeal Davidson's ruling.

"We clearly have authority to stop those vehicles, and forfeitures arising from criminal activity discovered in those stops are not implicated in this ruling," DOT spokeswoman Andrea Henry said.

Glen Downey, the attorney for Mansor, said the ruling speaks for itself.

"The law is clear, and the DOT's powers are limited," Downey said.

Gas-tank cash sign of crime?

Killpack, the DOT officer, first spoke with Mansor while standing in line at a Subway restaurant in Avoca.

Killpack said he followed Mansor, a resident of Laramie, Wyo., because "something did not feel right," court records show.

He ultimately stopped Mansor, 38, for allegedly traveling 75 in a 70 mph zone along Interstate Highway 80 in Pottawattamie County.

Killpack deployed a drug dog, who signaled an alert, even though no drugs were found in Mansor's truck.

The dog's alert gave officers the authority to search the truck, where they found the money in the gas tank.

Killpack wrote in a report following the stop that Mansor made "excited utterances that it (cash in vacuum-sealed bundles) wasn't his money," a statement Downey said is a lie.

Killpack's report also indicates multiple receipts and a "drug ledger" was found with detailed notes such as "30 @ 2400," which he contended in the report represented 30 pounds of marijuana at $2,400 a pound.

Mansor denies the note was present, and Downey said it is clear it is not in his client's handwriting.

Mansor never received a speeding ticket, nor was he arrested for a crime, following his stop by Killpack.

His truck, a Ford F-250 valued at around $11,000, was damaged by the search after officers "tore it apart to find the cash and drilled a hole into it," Downey said.

It's not illegal to travel with large sums of cash, but Iowa officers — whose agencies keep the profits of forfeitures — often try to connect money with crime, frequently citing motorists' conflicting statements as an indication of wrongdoing.

Some Iowa officers routinely conduct searches of vehicles after stopping them for going as little as 2 mph over the limit, according to an ongoing lawsuit alleging widespread abuse.

Iowa law does not require successful forfeitures be tied to criminal charges or convictions.

The state has seized more than $55 million in cash from more than 19,000 people and at least 4,200 vehicles since 1986, a Des Moines Register investigation last year showed.

Several personal libertarians and civil rights groups, as well as lawmakers from both parties, have condemned the controversial tactics, commonly known as "civil forfeiture."

They are the subject of multiple ongoing reform efforts nationally and in Iowa.

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The DOT has no other pending forfeiture cases, said Henry, the agency spokesperson.

The agency's officers helped seize at least $286,000 in two other stops since 2013, records show.

Almost all of those profits, $257,400, were distributed to the DOT, while the rest went to other law enforcement agencies, state records show.

Law enforcement agencies have long said forfeiture is a tool that allows officers to target the finances of criminal drug rings. Drug cartels are known to carry illegal substances and money in separate vehicles, making criminal convictions challenging, advocates of forfeiture have said.

The Iowa Police Chief Association, the Iowa Peace Officers Association and the Iowa State Police Association have lobbyists who have registered against a law that would require a criminal conviction before law enforcement agencies could successfully forfeit property valued at $5,000 or less.

Messages to the board presidents of the three Iowa associations that oppose the bill, Senate File 446, were not returned this week.

Other groups, including the American Civil Liberties Union of Iowa and U.S. Justice Action Network support the bill, which is awaiting a signature by Gov. Terry Branstad.

Interested in investigative Iowa news? Follow @JasonClayworth on Twitter.