With 5:42 remaining in the fourth quarter in the game at the Capital One Arena on Wednesday and with the Nets leading 109-103, Vanterpool reached out onto the court from the bench and deflected a pass from Wizards guard Spencer Dinwiddie to Kyle Kuzma.
The incident caused the Wizards to lose the ball and the officials missed the incident, something referee crew chief Ben Taylor confirmed in the pool report after the game.
It resulted in a chaotic few minutes as Washington players expressed their anger at the officials. The team had already used their coach's challenge so the Wizards could not contest the decision.
Vanterpool was fined for "interfering with live play by reaching across the sideline and deflecting an opponent's pass," according to the NBA. The Nets, who went onto win the game 119-118, were also fined $25,000.
With Washington coach Wes Unseld Jr. in health and safety protocols, assistant coach for the Wizards and interim head coach Joe Blair expressed his shock at the incident.
"My reaction was utter disbelief. I've never seen, in my very long time in basketball, something happen like that that the referees didn't see," Blair said.
Kuzma did not mince his words in the post-game press conference when asked about the events.
"That was also horses**t too. Coaches should not be able to stand up. I get it if it's under two minutes. Everybody in the league stands up ... You've got Steve Nash blocking the ref's view. He can't see s**t. I don't know what to say. It's very unfortunate but you've got to just live with it."
Neither Vanterpool or the Nets have commented on the incident or the fine and the team didn't immediately respond to CNN's request for comment.