Terrence Williams, 25, of the Boston Celtics was arrested Sunday afternoon after an incident in a parking lot in downtown Kent, said Kent police spokeswoman Melanie Frazier.
The mother of Williams' 10-year-old son told police the former Rainier Beach High School basketball standout threatened her with a gun during a scheduled exchange of the boy.
She said Williams pulled out the gun and made threats following an argument during the exchange. Williams then left the parking lot where the exchange took place, but he was later located and taken into custody.
"We investigate and treat all cases such as this very seriously regardless of the status of those involved" said Frazier.
Police investigators have interviewed witnesses, and are still actively investigating this case at this time.
During his first court appearance Monday, Williams was ordered held on $25,000 bail. He faces another court appearance on Wednesday.
Williams was drafted in 2009 by the New Jersey Nets. On March 3, 2013, Williams signed to a multi-year contract with the Celtics after playing sparingly for the team in the last season.
His status with the team is unclear following his arrest.