The NBA would not have allowed the Dallas Mavericks' trade for Kristaps Porzingis with the New York Knicks to be executed if they believed the sexual assault case again him appeared to be strong, according to a source briefed on the trade call.

The New York Knicks made the Mavericks aware of a potential "extortion issue" with Porzingis during the trade call.

The New York Police Department and the Manhattan district attorney’s office have confirmed an investigation against Porzingis is ongoing. 

The NBA will wait until the investigation plays or further developments before deciding on any action against Porzingis. 

The Mavericks aggressively pursued a trade for Porzingis and planned to offer him a five-year max contract worth $158 million in July. Mark Cuban declined to answer on Monday when asked if the Mavericks remain eager to sign Porzingis to that contract.