The journalist had sent the email to the Tehelka management about the incident which had taken place in Goa during an event about a fortnight ago.
The team will also seek copies of Tejpal's reply to the allegations from her.
Delhi police said that its Crime Branch will assist the special investigation team of Goa Police and provide them all the logistical and other support.
"We would provide them full support," said a senior Delhi police official.
The team is also expected to meet the victim and try to get an independent statement from her. They would also seek to convince her to file an official complaint as well.
The Crime Branch team led by a Deputy Superintendent will then question Tarun Tejpal and record his statement, who may be arrested in this case.
Goa Police had yesterday filed an FIR against Tejpal under Sections 376 (rape), 376 (2) (rape by a person of a woman in his custody taking advantage of his official position) and 354 (outraging modesty) of IPC in connection with the incident.
Conviction under Section 376 of IPC entails a maximum of life term in jail.
The issue came into limelight when the email by the woman journalist of his magazine alleging sexual assault was made public and Tejpal announced on Wednesday night that he was "recusing" from his job for six month.