6. Police can seize cash that they find if they have probable cause to suspect that it is related to criminal activity. The seizure happens through a civil action known as asset forfeiture. Police do not need to charge a person with a crime. The burden of proof is then on the driver to show that the cash is not related to a crime by a legal standard known as preponderance of the evidence.

5. An officer may expand a roadside investigation if the driver’s responses and other circumstances justify a belief that it is more likely than not that criminal activity is occurring. Under this standard, known as probable cause, an officer can make an arrest or search a vehicle without permission. An alert by a drug-sniffing dog can provide probable cause, as can the smell of marijuana.

4. A traffic infraction or reasonable suspicion alone do not give police authority to search a vehicle or a closed container, such as luggage. Police may ask for permission to search; drivers may decline. Police do not have to tell drivers that they have a right to refuse.

3. The officer also has the authority to briefly detain and question a person as long as the officer has a reasonable suspicion that the person is involved in criminal activity. Reasonable suspicion is based on specific and articulable facts but falls short of the legal standard for making an arrest.

2. An officer may detain a driver only as long as it takes to deal with the reason for the stop. After that, police have the authority to request further conversation. A motorist has the right to decline and ask whether the stop is concluded. If so, the motorist can leave.

1. Police have a long-established authority to stop motorists for traffic infractions. They can use traffic violations as a pretext for a deeper inquiry as long as the stop is based on an identifiable infraction.

Know your rights: During traffic stops on the nation’s highways, the U.S. Constitution’s Fourth Amendment protects motorists “against unreasonable searches and seizures.” The law also gives police the power to investigate and act on their suspicions.

The officer asked Molina, who had no criminal history, to hand over the cash. The officer placed the money in an envelope, which he set down on the ground alongside two empty envelopes.

A dog called to the scene sat down next to the envelope with the cash, indicating the presence of drugs, according to police.

The police took the money, but Molina took steps to get it back.

He hired David Smith, an Alexandria attorney and former federal prosecutor who once headed the federal government’s forfeiture program in the Eastern District of Virginia.

After Molina appealed, a federal prosecutor refunded the money. It took four months.

Smith said the Molina case is an example of the kind of overreach that the civil asset forfeiture reforms passed by Congress in 2000 were aimed at preventing.

“This type of police bounty hunting is antithetical to everything our criminal justice system is supposed to stand for,” said Smith, who helped craft the reform legislation.

Among the indicators police look for are rental cars, which are often used by smugglers.

On Nov. 1, 2011, Jose Jeronimo Sorto and his brother-in-law, Victor Ramos Guzman, were driving a rented sedan on I-95 south of Richmond when a Virginia state trooper stopped them. Both were lay leaders of the Pentecostal Nuevo Renacer church in Baltimore. They were carrying $28,500 in church funds meant for the purchase of land to build a church in El Salvador and a trailer for a new congregation in North Carolina.

Their experience has been cited as a case study in civil forfeiture abuse by The Post’s editorial page, the New Yorker magazine and others. Unknown until now in the public debate is the fact that the trooper who made the stop, C.L. Murphy, is a top interdiction trainer for Virginia State Police and Desert Snow, as well as a member of Black Asphalt.

Murphy told Sorto and Guzman that they were speeding and following too closely. Murphy said Guzman told him about the cash and consented to a search of the car.

Guzman, 39, of Sterling, Va., said he showed the trooper documents indicating that he belonged to a tax-exempt church, and he said the cash had been collected from congregation members. But Murphy disregarded their explanations, saying they contained inconsistencies. He called Immigration and Customs Enforcement, which accepted the seizure for the Equitable Sharing Program, and he escorted the men to a nearby police station. He did not issue a ticket but seized the cash after Guzman signed a waiver.

Three lawyers agreed to represent the church members for free. Three months later, they received a check from ICE for $28,500.

Virginia State Police spokeswoman Corinne Geller would only say, “The facts of the stop speak for themselves.”

ICE spokeswoman Marsha Catron defended the seizure, saying in a statement “the situation was indicative of bulk cash smuggling” and that Guzman consented by signing a waiver for the money.