Los Angeles Police Department detectives are investigating the incident as a possible hate crime and are examining security-camera footage from nearby homes in an attempt to identify the perpetrator.
The LAPD says the slur was painted over Wednesday morning.
The news conference was supposed to be about the start of the National Basketball Association finals Thursday - but the first question to LeBron James wasn't about dealing with the Warriors' Draymond Green.
Police spokeswoman Capt. Patricia Sandoval says the property manager told officers that they believe the incident was captured on surveillance video.
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The 18-year-old was killed in the blast shortly after her favourite artist Ariana Grande left the stage at the Manchester Arena on Monday.
According to publicly available records, James purchased the home in Los Angeles's tony Brentwood neighborhood for just less than $21 million in 2015.
"I can't be home to see my boys right now", James said. "You know hate in America, especially for African-Americans, is living every day".
The most unfortunate aspect of his situation, James said later, was that he couldn't be with his children to talk about it with them.
It was hard for James to think that he won't be home with his family until next week and he said he would settle instead for a FaceTime call, saying, "It's kind of killing me right now". He thanked his wife, Savannah, and other family member for handling some tough conversations to come once his two sons, Bronny and Bryce, got home from school.
"I'm at a point in my life where my priorities are in place", James said. "But to do his legacy any justice, let's use this moment as a call to action to all professional athletes to educate ourselves, explore these issues, speak up, use our influence and renounce all violence and, most importantly, go back to our communities, invest our time, our resources, help rebuild them, help strengthen them, help change them. And basketball is not the most important thing in my life".