Metro Transit Police are seeking public assistance in identifying a woman who they say poured a cup of urine on a bus operator.

Police released a photo of the woman allegedly responsible for the incident, which occurred on an X2 bus on Saturday, August 26 shortly before 6:15 p.m. near the intersection of Minnesota Ave and Benning Road NE. Throwing urine on someone is considered assault.

Metro bus drivers have a dangerous job, and have had to deal with a rise in threats and attacks from passengers.

D.C.’s new fleet of articulated buses, launched in November 2015, includes Plexiglass shields for drivers, which will appear on all future bus orders as well.

The shields aren’t bulletproof, but they are “spit and drink-proof,” Jim Hamre, director of Metrobus planning, told DCist in 2015. “That’s what we get the most of.”

But even if assaults on bus drivers are not unheard of, some longtime D.C. newshounds say that the use of urine is new.