Northern Ireland Electricity says a worker was threatened by masked men in Londonderry on Wednesday evening and ordered to take a suspect package to a police station.
He was carrying out repairs at Linsfort Drive in Creggan when the incident happened at around 9.30pm on Wednesday.
The NIE worker managed to run away and his van was found burnt out a short time later.
Twenty homes were left without power in the area.
An NIE spokesperson said the worker was ordered to take a suspect package to Strand Road police station.
“During an investigation into a fault on the underground electricity network in the Creggan area last night, an NIE emergency worker was approached and asked to take a suspect package to a local police station,” he said.
“The worker managed to escape the scene but his vehicle was set alight.”