Around midnight Friday night, with a week to go in a summer session, a group of female students decided to go for a swim in a fountain on the campus of the University of Maryland, authorities said.

The women stripped down to their underwear and placed their belongings nearby, said the campus police department. But as the women swam in the McKeldin Mall fountain, police said, a group of about 10 people approached and took their property.

In addition, police said, one of the female students also reported that her buttocks had been grabbed by one of the men in the group of 10.

The campus police sent out a crime alert to the campus, reporting a sex assault and theft.

After taking the women’s property, the interlopers fled from the area, police said, leaving a trail of items across campus.

Police said the trail ended near the Mowatt Lane parking garage, about a half mile away.

Much of the victims’ property was recovered, but a few items were still missing, the crime alert said

The McKeldin Mall fountain is a sizable expanse of water, measuring 16 feet by 250 feet, set in the grassy mall that lies just east of the main campus library, one of principal campus landmarks.