H.S. Indirect Technical Foul

[TRef21]

3:30 left in the 2nd quarter team A calls timeout. After the expiration of the timeout Team A inbounds the ball at there baseline. Team B coach is telling the official that there are only 4 players on the floor while the ball is already in play.
Team A puts up the shot sinks it. The trail official whose back is turned to the the team A bench sees a player just run on the court and goes right by him. The official blows the whistle and assess an indirect technical foul, for the illegal substitution. Team B coach starts saying he was already a starter and he can legally enter the game if four guys are on the playing court while the ball is live
(shows how much the coach knows the rules). He said that the official never saw the player run on from the bench. So the official goes to the able and the scorer, and both books say he ran on. The Crew chief comes over and tells the official, since you didn't have definite knowledge we can't assess it. The official had checked with the table personal, an extension of the officiating crew as well. The crew chief still doesn't penalize the illegal substitution. What is the correct ruling? Indirect Technical foul for the illegal substution or leave it alone since neither official say it with their own eyes.
you make the call..........