A section of cable was removed from England's Newbury course by power authorities for closer examination.
The meeting was cancelled following the sudden deaths of Fenix Two and Marching Song just before their jockeys were to mount up for the first race.
The race was run before a decision was made to cancel the meeting.
While authorities are stressing that all possible causes are being explored, it seems increasingly likely the horses were electrocuted.
The two horses that died were wearing metal shoes. Two who appeared affected but survived - Kid Cassidy and The Merry Giant - were wearing alloy racing plates.
Authorities say the results of the post-mortem examinations on the two horses will not yet be revealed.
British Horseracing Authority head of communications Paul Struthers, said investigators were not in a position to release the post mortem results on Monday: "Our investigation, which is running in tandem with the investigation being undertaken by Newbury Racecourse and Southern Electric Power Distribution, has a number of other aspects.
"It is therefore only right and proper that we do not make any announcement until we have received and thoroughly reviewed the results from the post-mortem and other analysis."
Discussions are also still ongoing as to whether the fixture will be rescheduled.
"We have been in discussions with all relevant parties and will make an announcement as soon as we are able," Struthers saidd.
"As the independent regulator of the sport, the safety and welfare of the horse is paramount - as it is for Newbury racecourse and for all of those who work in, and follow, racing.
"We must therefore ensure that, ahead of the meeting, we are satisfied from the post-mortem and our other analyses, and from Newbury racecourse, that there are no outstanding issues."