The two women who staged the Moscow metro attacks were among 30 people recruited by militant leaders to carry out suicide bombings, a report said on Thursday.
The Kommersant daily quoted sources close to the investigation as saying the men and women were largely recruited through the Internet and trained in the troubled North Caucasus region of Chechnya.
The two women who staged the Moscow bombings which killed 39 people on Monday are believed to have taken a bus from the Dagestan town of Kizlyar, where a double suicide bombing killed 12 on Wednesday.
Kizlyar is just over the regional border from Chechnya and has good train and bus connections to the Russian capital, Kommersant said. It said the women were trained in the Vedensky district of Chechnya.
The two women are believed to have arrived in Moscow by bus early Monday just before carrying out the attacks at two subway stations, reports have said.
"The investigation is now looking at the possibility that the metro suicide bombers were products" of the Vedensky camp for potential suicide bombers, Kommersant said.
An investigator told the newspaper that the group had been recruited after "young people who read the sermons of the Wahhabists on the Internet wrote to them and this often resulted in meetings with emissaries of the militants."
Wahhabism is an austere strain of Islam prevalent in Saudi Arabia.
It said that among the militant leaders who prepared the group was Islamist guerrilla leader Alexander Tikhomirov, also known as Said Buryatsky, a convert to Islam originally from Siberia.
He was killed by security forces in early March.
Kommersant said the investigators' information was the basis for Prime Minister Vladimir Putin's comments that the Moscow and Dagestan suicide strikes could have been the work of the same group.
The paper said investigators were now urgently seeking information on a 20-year old woman who is the widow of a Chechen militant leader killed in October. She has since gone missing and relatives were unaware of her location.