Grand Slam Track are investigating alleged abuse of Team USA's three-time Olympic gold medallist Gabby Thomas.
The incident took place at an event in Philadelphia before the 200m race in which Thomas was beaten by Melissa Jefferson-Wooden.
Following the race, an account called 'Mr 100k a day' posted a video heckling Thomas at the start line with the caption: "I made Gabby lose by heckling her. And it made my parlay win."
Thomas responded to the post, saying: "This grown man followed me around the track as I took pictures and signed autographs for fans (mostly children) shouting personal insults - anybody who enables him online is gross."
In a statement to The Athletic, Grand Slam Track event organisers said: "Grand Slam Track is conducting a full investigation into the reprehensible behaviour captured on video.
"We are working to identify the individual involved and will take appropriate action as necessary.
"We will implement additional safeguards to help prevent incidents like this in the future. Let us be clear, despicable behaviour like this will not be tolerated."
