Three Sunderland players have been cautioned for firing a pellet gun from a car window as they drove by.
Chris Brown, 19, Sean Taylor and Ryan Bell, both 18, were arrested and formally cautioned for public order offences by Northumbria Police.
Police received reports of a pellet gun fired at passers-by around Sunderland and Seaburn on Monday.
Niall Flynn, 18, was arrested and bailed following a separate alleged incident on Saturday.
Mr Brown has been a non-playing substitute for Sunderland's first team and played on loan for Doncaster last season. The other three players are trainees.
A Northumbria Police spokesman said at 1840 BST on Monday, police received a report of youths firing a pellet gun at passers by from a car driving along Durham Road, near Plains Farm, Sunderland.
The police spokesman said the caller reported a woman had been hit by a plastic pellet.
Firearms officers attended the scene and were searching the area when a further call was received from a woman reporting a plastic pellet had been fired at her from a car in Dykelands Road, Seaburn. There was no report of injury.
The spokesman said three men, two aged 18 and one aged 19, were arrested and formally cautioned for public order offences.
Police described the gun as a high powered toy gun capable of firing paint and harder pellets.
A Sunderland spokesperson said: "Sunderland Football Club can not condone such behaviour and takes this incident very seriously.
"The individuals involved have apologised for their actions, which they realise were both irresponsible and unacceptable.
"Whilst the players have been cautioned by the police, they will also face internal disciplinary measures by the club."
In a separate incident, a Northumbria Police spokesman said a 40-year-old man was walking with his daughter along Whitburn Road, in Sunderland, at 1945 BST on Saturday, when he was allegedly hit by a missile from a passing car and suffered a minor injury to his arm.
He said an 18-year-old man was arrested for assault, public order offences and motoring offences and is currently on bail pending further inquiries.