11:33 AM PT -- The NBPD just released a statement on the Josh Giddey investigation ... saying officials are actively seeking more information and pursuing all leads and evidence to get the facts of the case.
NBPD says the investigation remains active ... and is working to conduct a "fair and thorough" process.
The inquiry into whether Oklahoma City Thunder guard Josh Giddey had an inappropriate relationship with a minor has hit a roadblock -- TMZ Sports has learned the alleged teen and her family are refusing to cooperate with officials.
Law enforcement sources tell us police would obviously like to speak with the purported female and those close to her to gather more information regarding the social media claims that made rounds over the weekend ... but as of right now, no one is talking.
It's a significant component to the whole situation ... as a lack of cooperation will make it much more challenging for officials to determine whether any laws were broken.