Hearing witness: Yes it is possible
Hearing suspects/persons accused:
Hearing suspects(accused) persons is possible under Estonian legislation. § 468. Telehearing of persons staying in foreign states (1) Telehearing of a person staying in a foreign state may be requested on the bases provided for in subsection 69 (1) of this Code. The request shall set out the reasons for telehearing the person, the name of the person to be heard and his or her status in the proceeding, and the official title and name of the person conducting the hearing. (2) If audio-visual telehearing is requested, the request shall contain an assurance that the suspect or accused to be heard consents to the telehearing of him or her.