The police say Mr Bach is being treated as a witness, not a suspect.
Officers have found emails from Mr Bach to another senior IOC official Patrick Hickey, who was arrested last month and is facing charges.
Mr Hickey, ex-head of the Irish Olympic Committee, denies all allegations.
Police investigators in Rio told the BBC's Wyre Davies they would like to know what Mr Bach's influence was over Olympic ticketing policy.
They said the IOC president received personal requests for hundreds of high-value tickets, for the Olympics opening ceremony, the 100m final and the football final from Mr Hickey.
Police say that Mr Hickey received 296 tickets after his written request to the IOC president.
They have not, thus far, made any contact with the president's office to request a formal interview.
Mr Hickey was arrested during the Olympic games and spent time at the notorious Bangu high security jail along with fellow Irishman Kevin Mallon.
He was released on bail at the end of August but had to return his passport to the Brazilian authorities and was ordered not to leave the country.
A prosecutor laid charges against him on Tuesday. A judge will now decide whether to accept or reject the charges.
Mr Hickey, 71, has formally stood aside as president of the Olympic Council of Ireland and European Olympic Committees' president during the investigation.
Mr Mallon is the Dublin-based director of THG Sports, a corporate and sports hospitality company.
Mr Bach cancelled a planned appearance in Rio this week at the opening of the Paralympic Games, for personal reasons.
Mr Bach has not returned to Rio since the Olympics and missed the opening ceremony of the Paralympics at the Maracana on Wednesday.
He said would remain in Germany for the funeral of his friend Walter Scheel, the former West German foreign minister and deputy chancellor, who died last month aged 97.
IOC officials said Mr Bach would now not travel to Brazil after the funeral because he was unable to reschedule other commitments.
The Paralympics run until 18 September.
The last time an IOC president failed to attend a Paralympics was in 2010, when Jacques Rogge missed the whole of the Winter Games in Vancouver.

US experts found B3, also known as nicotinamide, boosts the ability of immune cells to kill Staphylococcus bacteria.
B3 increases the numbers and efficacy of neutrophils, white blood cells that can kill and eat harmful bugs.
The study, in the Journal of Clinical Investigation, could lead to a "major change in treatment", a UK expert said.
B3 was tested on Staphylococcal infections, such as the potentially fatal MRSA (Methicillin-resistant Staphylococcus aureus).
Such infections are found in hospitals and nursing homes, but are also on the rise in prisons, the military and among athletes.
The scientists used extremely high doses of B3 - far higher than that obtained from dietary sources - in their tests, carried out both on animals and on human blood.
And the researchers say there is as yet no evidence that dietary B3 or supplements could prevent or treat bacterial infections.
The researchers say B3 appears to be able to "turn on" certain antimicrobial genes, boosting the immune cells' killing power.
Prof Adrian Gombart, of Oregon State University's Linus Pauling Institute, who worked on the research, said: "This is potentially very significant, although we still need to do human studies.
"Antibiotics are wonder drugs, but they face increasing problems with resistance by various types of bacteria, especially Staphylococcus aureus.
"This could give us a new way to treat Staph infections that can be deadly, and might be used in combination with current antibiotics.
"It's a way to tap into the power of the innate immune system and stimulate it to provide a more powerful and natural immune response."
Prof Mark Enright, of the University of Bath, said: "Neutrophils  are really the front line against infections in the blood and the use of nicotinamide seems safe at this dose to use in patients as it is already licensed for use.
"This could cause a major change in treatment for infections alongside conventional antibiotics to help bolster patients immune system.
"I would like to see in patient clinical trials but cannot see why this couldn't be used straight away in infected patients."
Brazilian police say they want to speak to International Olympic Committee (IOC) president Thomas Bach about an alleged scheme to resell tickets during last month's Rio Olympics.
[NEXT_CONCEPT]
Vitamin B3 could be the new weapon in the fight against superbugs such as MRSA, researchers have suggested.