(CNN)Claudia Choi says that after her father was laid to rest, her elderly mother received a "cruel" letter in the mail threatening Asian Americans.
"I was angry. It fired me up," she told CNN. "It didn't make me want to cry because my tears are saved for (the) loss of my dad. But it made me want to let people know this is happening."
Byong Choi passed away on February 24 and his funeral was on Friday, Choi said.
The Seal Beach Police Department in California said in a news release it is investigating the letter as a hate crime. This comes just days after eight people -- six of whom were women of Asian descent -- were killed in Atlanta-area spas, a tragedy that ignited nationwide conversations about the hostility and discrimination Asian Americans face in the US.
Seal Beach police said they received a call on Monday about a resident in the retirement community Leisure World who had received a threatening letter.
"Now that Byong is gone makes it one less Asian to put up with in Leisure World," the handwritten letter said in part.
"Watch out," it added. "Pack your bags and go back to your country where you belong."
Police said they're conducting DNA and fingerprint analysis, handwriting analysis, neighborhood canvasses and video surveillance reviews to determine who was the author.
"Hate directed toward any member of our community is disgusting and will not be tolerated," Philip L. Gonshak, the police chief, said in a statement.
"We are seeing more and more violence committed against Asian Americans and Pacific Islanders. We will not allow this to happen in Seal Beach," the chief added. "Our investigators are working hard to following up on any and all leads we receive."
The letter dehumanizes Asians, Choi said, noting the lengths the author had to go to send it.
"The person took the time to write it longhand, it looked like a second or third draft, it was carefully folded, then they had to find a stamp," she said. "During all that time he/she could have turned around and said, 'Maybe I'll keep my racist views to myself.'"