Police opened an investigation on Monday into an assault complaint filed against David Nalbandian after the Argentine tennis player kicked an advertising board and injured a line judge during the Queen's Club final.
London police declined to say who made the complaint against Nalbandian, who was defaulted from Sunday's match against Marin Cilic in the grasscourt Wimbledon warmup event.
Any member of the public who witnessed the event in person or on television could have made a complaint, as could the line judge himself.
"We are aware of an incident at the Aegon Championships,'' the Metropolitan Police said in a statement.
"A complaint has been made and the Metropolitan Police Service is now investigating. The allegation is of assault.''
"A complaint has been made and the Metropolitan Police Service is now investigating. The allegation is of assault"
Metropolitan Police statement
Nalbandian won the first set 7-6 (3) but lost his temper after losing serve to fall behind 3-4 in the second.
After missing a running forehand on game point, he kicked the board under the chair of line judge Andrew McDougall. A piece of the board cut the judge on the left shin, leaving him bloodied from an inch long gash.
Tournament director Chris Kermode said McDougall received first-aid care but needed no further treatment after seeing a doctor.
Nalbandian was disqualified for unsportsmanlike conduct. ATP rules state that any violent action will result in an automatic default.
Nalbandian also was stripped of his $57,350 in prize money and could face a fine. He is still scheduled to play at Wimbledon, which starts on Monday.
Nalbandian insisted he shouldn't have been disqualified.
"Sometimes you get very frustrated on court and it's tough to control that, and sometimes I do a mistake. So it's very tough to end a final like that,'' he said.
"I agree I do a mistake but sometimes everybody do a mistake and I didn't feel it had to end like that, especially in a final.''