The club issued a statement after another Scottish Premiership club admitted to being targeted.
A statement from the Tynecastle club said: “Heart of Midlothian can confirm it was the subject of an internet fraud earlier this year.
“The matter is now part of an active police investigation and therefore no further comment will be made.”
Hamilton Academical also claimed it was the target of an “elaborate” financial fraud, which resulted in it losing “a substantial sum of monies”.
The side, based at New Douglas Park in North Lanarkshire, is now cooperating with Police Scotland and its bank to “pursue the individuals responsible”, it said in a statement published on Friday.
It said: “At this point it is imperative that we remain calm and work together as we go through one of the most difficult situations we have faced as a club.
“In the interim, the directors intend to inject funds to meet the club’s ongoing obligations until the investigation is complete to ensure continuity. It is our intention to host a media briefing to go into more detail when the initial legal and banking investigations reveal the facts.”