As much as 90 percent of the currency circulating throughout the United States contains trace amounts of cocaine. No one would expect the police to claim someone’s money must be “dirty” based on trace presence of drugs alone. But that is exactly what law enforcement officers in Brown County, Wisconsin, claimed when they seized money from a mother attempting to post bail for her son.

When Joel Greer was arrested by the Brown County Drug Task Force, a judge set his bail at $7,500. As any good mother would, Beverly Greer immediately set to work gathering the funds necessary to free her son. Beverly called the Brown County jail, where Joel was being held, and was explicitly told to bring the bail in cash—even though Wisconsin law allows you to pay for a bond with a cashier’s check, credit card, money order, or cash. A series of visits to ATMs secured the $7,500, and Mrs. Greer reported to the jail to bring her son home.

But rather than accept the cash and release her son on bail, Brown County police brought in a drug dog, which alerted to the trace amounts of illegal drugs on the bills. Brown County police then seized the cash and refused to release Joel Greer. The police chose to ignore the ATM receipts proving the money had originated at a bank and claimed it was drug money. In reality, it was the family’s hard-earned savings and Mrs. Greer’s disability pay.

The Greers didn’t get their money back for four months—and only after an attorney got involved on their behalf. Under Wisconsin law, law enforcement authorities may keep half of any seized amount exceeding $2,000, creating a perverse incentive for local law enforcement. In this case, it was obviously tempting enough that the authorities tried to deprive a man of his right to post bail and to essentially rob a family of its money.

And they are not alone. Another victim, Jesus Zamora, was arrested on misdemeanor charges, and when his girlfriend turned up with $5,000 in borrowed money to bail him out, the police seized it after a canine inspection. Zamora remained in custody until an additional $5,000 could be scrounged together—this time turned over straight to a judge in the form of a cashier’s check.

If you can’t trust the police to apply the laws fairly, whom can you trust? The fault for this bait-and-switch does not lie with the police alone, though. It lies with civil asset forfeiture’s perverse incentives and lax standards, which all too often result in enriching abusive law enforcement authorities at the expense of American citizens.