The IOC Executive Board appointed a three-man commission in Berlin to determine whether Helmick's financial dealings represented any conflicts of interest.
Helmick has been a member of the IOC -- a lifetime post -- since 1985. He has also been serving a four-year term on the IOC's 12-member executive board since 1989.
Though officials declined to speculate on Helmick's IOC future, they did not rule out the possibility that he could be forced to leave his post if the inquiry confirms wrongdoing.
IOC officials apparently were shocked by disclosures in the United States that Helmick had worked as a paid consultant for several firms connected with the Olympic movement. USA Today reported that Helmick earned at least $127,000 for the work in 1990.
Helmick attended the IOC meeting in Berlin on Tuesday, asking the executive board to defer any action on his case until the USOC's inquiry was complete. The board agreed.
Helmick returned to the United States, where he announced his resignation Wednesday. He denied any wrongdoing but said the controversy was making it impossible for him to carry out his duties.
After Helmick's resignation, the IOC moved to begin its own probe.
The three-man inquiry commission, announced yesterday, is headed by IOC vice president Keba Mbaye.
The committee was asked to report its findings at the board's December meeting.
* The IOC has rejected physical examinations and decided to retain saliva tests for verifying the gender of athletes.
The issue was raised yesterday at the executive board meeting by the chairman of the medical commission, Alexandre de Merode.
IOC spokeswoman Michele Verdier said proposals to switch to physical tests were turned down mainly due to ethical objections.
Instead, the medical board found that the IOC's long-standing procedure of taking saliva samples remained the most effective test.
However, in cases where saliva tests prove insufficient, the IOC will check the athlete's level of testosterone -- the male sex hormone. As a last resort, the athlete will be asked to submit to a physical exam.
The IOC decision counters the action taken recently by the International Amateur Athletic Federation, the governing body for world track and field.
Saying saliva tests were "scientifically unreliable," the IAAF switched to physical gender exams starting with the recent world championships in Tokyo.
* On another medical matter, the IOC said it is still studying the possibility of using blood tests to check athletes for doping.
Officials believe blood could be more effective in detecting banned substances than urine samples.
A final report on the issue will be presented at the next IOC board meeting in December.