INDIANAPOLIS -- Authorities in Indianapolis have intensified the search for two men who forced six boys to give urine samples in a park.

The incident happened at Chapel Hill Park on the city's west side, according to local station WRTV.

"He came home crying and sweaty and said, 'Mom, I took a drug test,'" said one of the boys' mother, who did not want to be identified.

The impersonators took the boys one-by-one and demanded they submit to a drug test out in the open at the park.

"They opened up the police car, handed them a cup and had them use it in the cup," the mother said. "They made them sit down on a picnic bench afterwards and … told them, 'OK, go home.'"

Police said a woman who was also in the park at the time of the attack witnessed the boys with their pants down and questioned the activity.

The incident happened around 5:30 p.m., when the would-be rangers arrived in what appeared to be an older-model, white Ford Crown Victoria with a portable red light inside.

"Obviously, it's disturbing any time someone violates the public's trust by impersonating a police officer, but it's particularly disturbing when they would violate the trust of a child," Detective Bob Pearsey said.

Police said there have been 80 cases of officer impersonation in Indianapolis in the last five years, but this is the first involving urine samples.