According to a police report, obtained by TMZ Sports, cops claim 49-year-old Joseph Bilgen was holding up offensive shirts and screaming profanity at LeBron and others during the big game.

Of course, with LeBron returning to his home state and playing the Cavs ... emotions were high -- and according to the report, several Cleveland players and employees, including GM Koby Altman, reported the fan to security.

Cops say they were informed the guy had held up shirts with offensive writing on them ... including, "Lebron is a racist," "La B**w J*b," and "Lebron is a narcissist."

Officers say when they confronted Bilgen about the inappropriate shirts and actions ... he became so combative -- security told officers he would have to be removed from the arena.

Bilgen, though, did not go quietly according to the report ... an officer says the man told him to "go f*** yourself" repeatedly, and at one point, even put his hands on the cop.

The report states as Bilgen was leaving, he then held up a shirt that read, "Gloria Goes West. Starring LBJ as king narcissist."

In the report, officers say that when a female security guard took the shirt from him, Bilgen grabbed her arms and struck her in her left side.

Officers say they were eventually able to boot Bilgen from the arena after several more minutes of struggling near the exits. Bilgen, according to Cleveland.com, was NOT arrested.

No charges have been filed against Bilgen, either, per Cleveland.com.