Authorities in Wichita, Kansas are searching for the person who allegedly anonymously harassed a biracial family living in their neighborhood, KSN-TV reported.

“These are kids under the age of 10 where me and their parents are trying to raise them, you have to love everybody, be friends with everybody,” said Nancy Wirths, whose family received a letter insulting her grandchildren. “It doesn’t matter if they’re brown, purple.”

Wirths said the unsigned letter arrived at her home on Monday, accusing her and her family of showing their neighborhood “a great disrespect” because of the children’s presence.

“We have noticed there are some black children at your residence,” the note read. “Maybe you are running a daycare or these are your children. In either case, we have put our house for sale. This neighborhood does not need any blacks in it.”

If caught, the person or persons responsible could face disorderly conduct charges. For her part, Wirths said she has not allowed the children to go outside since receiving the note.

“I hope this never happens to anyone else,” she said.