The Cheshire home of Manchester United executive vice-chairman Ed Woodward has been attacked by a group chanting that he was “going to die”.
A video posted on social media showed an individual throwing a red flare over a large gate, while others sang songs aimed at the 48-year-old.
Woodward, who is married with two young children, was not present at the time.
Manchester United said anyone committing a criminal offence or trespassing will be banned for life.
A club statement added: “Fans expressing opinion is one thing, criminal damage and intent to endanger life is another. There is simply no excuse for this.
“We know that the football world will unite behind us as we work with Greater Manchester Police to identify the perpetrators of this unwarranted attack.”
Woodward has been the subject of growing supporter discontent at United in recent weeks.
Manchester United sit fifth in the Premier League – 33 points behind leaders Liverpool – and Woodward has been the target of blame by many fans.
Both at the recent home game against Burnley and Sunday’s FA Cup victory over Tranmere, supporters have sung the same song about Woodward and made repeated calls for the club’s owners, the Glazer family, to leave.
The incident is reminiscent of another attack, in 2004, on the car of then club director Maurice Watkins, whose shares ended up being bought by Malcolm Glazer as his bid for the club gathered pace.
Woodward advised Malcolm Glazer and the Glazer family during its successful takeover of the club in 2005 before being recruited as a senior member of staff.
United play local rivals Manchester City in the Carabao Cup semi-final second leg on Wednesday and trail 3-1 on aggregate.