The FA have opened a spot-fixing investigation into suspicious betting patterns surrounding the booking of Oxford defender Ciaron Brown in Monday’s FA Cup defeat by Arsenal.

Sportsmail has learned that the FA have a dossier of evidence regarding supposed corruption, including alleged phone messages before kick-off at the Kassam Stadium which claim that Brown would be booked in a betting scam that allegedly cost one bookmaker more than £1,600.

One message is understood to show a betting slip with around £200 staked on Brown being yellow-carded at odds of 8-1.

The 24-year-old Northern Ireland defender was booked in the 59th minute for fouling Bukayo Saka with the score at 0-0, four minutes before Mohamed Elneny gave Arsenal the lead.

Eddie Nketiah’s brace then gave the Premier League leaders a 3-0 victory.

It is unclear how many bets were placed on Brown being booked and the extent of other bookmakers’ liabilities, but the FA is taking the matter seriously.

Eyewitnesses at the game told Sportsmail they saw several Arsenal fans celebrating after Brown was booked, with several of them bragging about winning hundreds of pounds.