"The military police of the state of Rondonia has already initiated an internal investigation into possible irregularities committed in that incident," police spokesman Lenilson Guedes told Reuters on Friday.
"We have already asked for local TV footage so we can analyse the images."
During the second half of a Rondoniense (state) championship match at the Aluizio Ferreira stadium in Porto Velho last weekend, officers resorted to pepper spray to try to get the dismissed players off the pitch, sparking a free-for-all.
The dismissals occurred in the 64th minute when Genus, who played in last year's Brazilian championship fourth-tier Serie D, were losing 3-0 to Moto Esporte Clube in one of the country's minor state championships.
"The players refused to go off (and) insulted the referee so he called the police who were on duty in the stadium to guarantee security (for the match officials)," Guedes said.
"Players are believed to have sworn at the police officers and one sprayed them."
Guedes explained the procedure the officers should have followed but appear to have been ignored.
In such incidents "the first approach must be oral, 'citizen, kindly leave the place', then they can be escorted out by the arm, the third stage would be to use a truncheon and the fourth the spray.
"This officer passed directly to the spray," said Guedes.
The Rondonia Football Federation said on its website that it had ruled the remaining minutes of the match would not be played and the result would stand.
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