Russia has been given three weeks by anti-doping chiefs to explain alleged "inconsistencies" in data from its Moscow laboratory.
The World Anti-Doping Agency (WADA) announced it opened a formal compliance procedure against the Russian Anti-Doping Agency (RUSADA) earlier this month.
WADA's intelligence and investigations department (I&I) is making "good progress" in analysing data retrieved from Moscow in January, with 47 suspected cases already identified.
However, answers are being sought over apparent discrepancies in data, which could lead to sanctions, including a possible ban from the 2020 Olympics, if Russia cannot provide satisfactory explanations.
WADA compliance panel chairman Jonathan Taylor told BBC Sport: "There's evidence this data has been deleted. We need to understand from the Russian authorities what their explanation is."
In a statement, WADA said: "The ExCo [executive committee] was also informed that further investigation, by WADA I&I and independent experts in digital forensics, of the inconsistencies in the Moscow laboratory data ... had led WADA to open a formal compliance procedure against RUSADA on 17 September 2019.
"Ensuring the authenticity of the Moscow laboratory information management system and underlying raw data was one of the critical conditions imposed by the ExCo for RUSADA to maintain its compliance with the code when the ExCo decided to reinstate RUSADA as code-compliant in September 2018.
"The ExCo was advised that WADA had decided to pursue the compliance procedure against RUSADA on a fast-track basis, in accordance with article 9.5 of the international standard for code compliance by signatories.
"RUSADA and the Russian Ministry of Sport have been provided with copies of the reports of WADA I&I and the independent forensic experts that detail the inconsistencies in question and have been given three weeks to provide their comments, together with answers to a list of specific questions.
"Once that response has been received and analysed, WADA I&I and the independent forensic experts will report back to the CRC [compliance review committee], so that the CRC is in a position to decide whether to bring a formal recommendation to the ExCo. No fixed timeline can be set for this, as due process must be respected, but the ExCo was assured that WADA is pursuing the matter robustly and as quickly as practicable."
Meanwhile, athletics' world governing body the IAAF said on Monday there had been no change in the status of the Russian Athletics Federation (RusAF), meaning the nation is banned from the upcoming World Athletics Championships.