The daughter of House Democratic Leader Katherine Clark, D-Massachusetts, was arrested during a protest in downtown Boston on Saturday and charged with assault after a police officer was injured.

clark tweeted Sunday about her daughter’s arrest, saying: «I love Riley, and this is a very difficult time in the cycle of joy and pain in parenting. This will be evaluated by the legal system, and I trust that process.”

The Boston Police Department alleges in a statement that officers observed Clark’s 23-year-old daughter deface a monument with spray paint with the words «NO COP CITY» and «ACAB.» During the arrest, “a group of about 20 protesters began to surround the officers while yelling profanity through megaphones on public roads, causing traffic to stop,” the statement said. One officer was struck in the face and was seen bleeding from his nose and mouth, police said.

Clark’s daughter was charged with assault with a dangerous weapon, destruction or injury to personal property, property damage by graffiti or tagging, and resisting arrest, and is expected to arraign in Boston Municipal Court, police said.

Clark has publicly expressed concern for his daughter, whom he says he identifies as nonbinaryin light of recent incidents of intolerance against the transgender community.