Three matches at the 2017 Wimbledon Championships have been flagged for further investigation, the Tennis Integrity Unit has announced.
Two matches in the qualifying rounds and one match in the main draw will be investigated for match-fixing. One match in the French Open will is also under scrutiny.
The four matches are part of 53 match alerts received by the TUI since April. The TUI monitors unusual betting patterns around players in all the professional tennis tours.
"During the second quarter of 2017, 53 match alerts were received," the TIU said in a statement.
"Consistent with previous reports, the majority of alerts [40 out of 53] were received for matches played on the lower level men's ATP Challenger and ITF Futures circuits.
"Roland Garros and Wimbledon…accounted for the four grand-slam alerts. These will be assessed and reviewed in keeping with the TIU match alert policy.
"Every alert is assessed and followed up as an indicator that something inappropriate may have happened, though an alert on its own is not evidence of match-fixing."
In the same period in 2016, 73 match alerts were received, indicating a drop in potential match fixing.