The fuller answer
When a friend discloses sextortion, grooming, assault, or another unwanted experience, the first job is not investigation. It is to believe the disclosure, reduce shame, check immediate safety, and help connect them with an adult or advocate.
A friend may tell only part of the story, change details, laugh, seem calm, or return to the person who caused harm. Trauma, fear, dependence, affection, and uncertainty can all affect disclosure. These reactions do not prove that nothing happened.
Do not promise absolute secrecy when someone is in danger. Explain honestly that you may need help from a safe adult, and involve the friend in choosing who and how whenever possible.