A mother in Seattle said she is struggling with how to explain racism to her mixed-race children after someone penned what police called a “threatening” and “racist” letter and put it on her doorstep.

Stephanie Endres said the letter, which she discovered Tuesday night, included racial slurs and talked about the Black Lives Matter movement.

“U and all these n—— need to leave this country that’s ours!” it said, according to the West Seattle Blog. “One day your kids will get what they deserve  being on this land. F—— n—– lovers! White lives matter f—— n—– lovers!”

It ended with the words: “Go Trump!”

“My kids are going to get what they deserve?” Endres told Fox affiliate KCPQ. “That doesn’t sit right for me.”

Seattle police said in a statement on Wednesday that the incident is now being investigated as a hate crime.

Police said they were called to Endres’s home about 10 p.m. Tuesday after she found the letter on her porch.

“I had a bunch of bags in our hands and stuff and then I saw a piece of paper there,” Endres told KCPQ.

Endres, who is white and has two mixed-race children, told ABC affiliate KOMO that her family has lived in the same house in West Seattle for 27 years and “never had issues.”

“I’ve never had anyone treat my kids differently for being mixed,” she said, “so it was really out of nowhere.”

Endres is the founder and executive director of Stephanie’s Lifeline/HOPE (Homeless Outreach Prevention and Education), a nonprofit organization based in Seattle. The group’s website states: “Stephanie’s Lifeline is dedicated to serving less fortunate individuals and families in order to improve the quality of life of those most in need.”

She appeared on the West Seattle Blog late last year during her group’s Backpacks Bring HOPE event, “filling 100 backpacks with basics — first-aid kits, toiletries, some food and beverages.”

Since Endres found the letter Tuesday night, she said, her community has rallied around her in support.

“It’s really sad there’s at least one person in our neighborhood that feels this way about it,” Stu Hennessey, a neighbor, told KCPQ, adding: “We’re trying to organize an effort to make them feel more welcome in our neighborhood.”

Seattle police said they are investigating the letter as “malicious harassment” or a hate crime. The police department’s website explains more about malicious harassment:

The reason the suspect targeted that particular person was based on their belief about the victim’s race, color, religion, ancestry, national origin, sexual orientation, mental, physical, or sensory handicap, homelessness, marital status, age, parental status, gender or political ideology.

If the suspect is mistaken about the victim’s status, but selected them because of the suspect’s belief about the victim’s status, it is still considered malicious harassment.

The Seattle Times reported last month that there were 208 hate crimes reported last year in Seattle, an increase from 126 in 2014. The number of hate crimes against African Americans has more than doubled, according to the newspaper.

On Tuesday night, Endres posted the racist letter on Facebook, saying she was glad her children “can’t read yet.”

“This hate has got to stop,” she wrote. “The coward who left this couldn’t even do it while we were home. Truly makes me uncomfortable to know people like this are in my neighborhood/community.”

Read more:

Aren’t more white people than black people killed by police? Yes, but no.

Why Obama may be wrong about freedom being more powerful than fear