Alexandria Wright, who now lives in Dallas, testified by video that officers "went too far" in their search, the Milwaukee Journal Sentinel reported.
"I saw his butt cheeks. Am I allowed to say that? I saw Leo's butt cheeks," Wright said.
Leo Hardy, 40, is one of about 50 people suing the city and police department, alleging that officers conducted improper strip and cavity searches. His federal trial, the first of potentially dozens, entered its second day Tuesday.
One former officer pleaded guilty to four felonies in connection with illegal searches, and three others pleaded no contest to related misdemeanors. All four were forced to resign.
Hardy is suing two other officers, as well as Police Chief Edward Flynn, the police department and the city.
Hardy testified that Officer Michael Gasser searched him by putting a bare hand down the front and back of his pants. Officer Michael Valuch Jr. also pulled Hardy's pants while Hardy was handcuffed outside a police wagon, and then pulled the waistband of Hardy's underwear away from his body and looked down his pants in both the front and back, Hardy testified.
A witness, Dorothy Lee Smith, said the search occurred while the police wagon was parked outside her home. She testified that Hardy's pants were around his ankles.
Strip searches can be conducted only with written permission from the police chief or a supervisor, and only when the officer expects to find a weapon. Even then, they cannot be done on the street.
Gasser's partner at the time, Keith Garland Jr., testified Tuesday that he and Gasser approached Hardy because he used to hang around a known trespasser. Garland said he didn't see Hardy commit a crime or traffic violation.
Gasser testified Monday that he searched Hardy because he smelled marijuana and that he felt a felt a softball-sized package of suspected marijuana while he was patting down the front of Hardy's pants for weapons.
Contradicting his former partner, Garland testified he didn't smell marijuana on Hardy.