SOFIA (Reuters) - A Bulgarian man who posted a video showing three Afghan migrants lying tied up on the ground near the Turkish border was acquitted on Tuesday of illegally detaining them, after a court ruled there was insufficient evidence against him.

Petar Nizamov, 31, nicknamed Perata, was arrested last April after posting the video on social media.

It showed two men lying on the ground with their hands tied behind their backs. A third man lay flat on his stomach, restrained with long plastic cable ties, while an unidentified voice shouted in English: “Go back. Back Turkey. Now. No Bulgaria, go Turkey immediately”.

All three men were later found by border police, no longer tied up, and were taken to an accommodation center for migrants.

The video was included as evidence but the regional court in Burgas said it could not confirm Nizamov’s participation since witnesses said they could not remember who tied up the migrants.

National television bTV reported that Nizamov thanked the judge, who he said was “one of the few courageous judges who oppose the organized trafficking of migrants”. He also told the court he intended to continue to patrol at the border.

Prosecutors plan to appeal against the court’s decision.

Tough measures to restrict asylum seekers and migrants are supported by all political parties in the Balkan country, which has built a wall along its border with Turkey.

Figures from Bulgaria’s Interior Ministry show the number of people officially detained at the Turkish border dropped to 64 in January, compared to 712 in January 2016.