Germany's largest power company suspects foul play after an 80-meter-high (260-foot) electricity pylon buckled but did not fall near the Garzweiler coal mine in North Rhine-Westphalia on Friday.
Police from the city of Aachen were alerted to the incident on Friday night and an investigation is underway.
"According to previous findings and assessments of the damage by experts from the network operator, the influence of third parties is likely," police said in a statement on Saturday.
The Garzweiler coal mine has been the site of large-scale anti-coal protests. Climate activists who occupied the deserted village of Lützerath to prevent an expansion of the mine clashed with police in January before they were forcefully evicted.
Swedish climate activist Greta Thunberg attended those protests in person and called the expansion of the mine "a betrayal of present and future generations."
RWE condemns 'sabotage'
RWE, the company that operates the coal mine and provides much of Germany's electricity, said it also believes the pylon was "deliberately damaged with the intent to make it collapse."
"If it was sabotage on critical infrastructure, we condemn it in the strongest terms," a spokesperson for the power company told Germany's dpa news agency on Saturday.
Technical experts secured the partly buckled pylon on Friday night after being alerted to the damage, and the coal mine continued to operate like normal.
As well as delivering power to the mine, had the pylon and the power line been rendered wholly inactive, a nearby water treatment plant might also have been affected.
"Because the electricity supply is stable, the water supply of Grevbenbroich from the RWE-run water facility in Fürth is not endangered," the RWE spokesman told dpa.
zc/msh (dpa, Polizei Aachen)