8:32 AM -- Cops say in a police report obtained by TMZ Sports that James Hill Jr. told them the assault was preceded by a series of disputes between him and his brother ... including one that involved the cleaning of Jamahal Hill's freezer.

In the docs, officers say James told them he had picked Jamahal up from a Michigan airport ... but when the two arrived at Jamahal's house a short time later, they realized that because the residence had been left vacant for months, the electricity in the unit had been turned off -- causing "all the food in the house to spoil and rot."

Cops say James told them he and Jamahal had agreed James would clean the house with his wife for $300. James said, according to the docs, "he cleaned out the whole house besides the chest freezer in the garage."

But, cops say in the police report James told them that after he and Jamahal got into an argument over the UFC fighter's alleged treatment of women and their own mother -- he left the home.

James, according to cops, said Jamahal texted him the next day and asked why he didn't clean out the freezer ... allegedly demanding half the money back for the unfinished job.

Police say James, however, came back on Nov. 25 to clean it all out ... and once he completed the task, he went to talk to Jamahal -- and another dispute broke out.

This time, according to the docs, James and Jamahal got into it over Thanksgiving Day texts. The argument, cops say James told them, then turned physical.

Officers say James told them Jamahal "sucker punched" him with a closed fist -- before hitting him a second time.

According to the docs, James left the home and debated on calling police because "he didn't want to ruin Jamahal's UFC fighting career." Though after Jamahal allegedly wouldn't respond to texts or apologize, he called cops to report the incident.

Former UFC light heavyweight champion Jamahal Hill allegedly got so violent during an altercation with his brother last month that he knocked a tooth right out of the man's mouth.

The allegations are spelled out in a probable cause affidavit, obtained by TMZ Sports.

In the docs, police say James Hill Jr. told them from a Kentwood-area hospital in Michigan that Jamahal had assaulted him on Nov. 25 after the two had gotten into an argument.

Jamahal, according to the docs, punched his brother once, sending him to the ground. Cops say when James got up, Jamahal punched him again -- hurling him right back to the floor.

According to the docs, James' face and left eye were "very swollen" after the alleged attack ... and officers also say James was "missing a front tooth that he stated got broke when Jamahal assaulted him."

Jamahal was arrested over the allegations on Nov. 27 ... and formally charged with one count of aggravated domestic violence shortly after. He's due in court for a hearing on the matter next month.

In a video Jamahal released on Saturday, the 32-year-old said he's "been advised not to speak on" the arrest ... though he did say, "I just can't wait for the truth to be told in court and I will wait for that day and I look forward to that day."

"The people who know me and know my character and truly, truly rock with me and know who I am, hold on to that and stay true to that and yeah, that's all I'm gonna say on that."