An employee working remotely is bound by the express and implied terms in her employment contract just as thoroughly as one working under direct management scrutiny. The implied terms, though not spelt out, form part of every employment contract, and include the obligation on the employee to serve the employer honestly and faithfully, and not to enter into competition with the employer's business. So you need to investigate more thoroughly, and if there is evidence to suggest that your suspicions are correct, consider activating your disciplinary procedure.
