Iliyan Filipov, owner of transport firm PIMK and boss of football club Botev Plovdiv, was shot dead with a single bullet to the head. The gunman had waited for him behind trees outside his block of flats in Plovdiv's Hristo Smirnenski district. Filipov was one of Bulgaria's most powerful businessmen, with many enemies and a long history of feuds.

A correspondent in Plovdiv says the killing has not left the city shaken. Filipov was one of the biggest investors in transport there.

He was close to former prime minister Boyko Borisov. He led a group of businessmen who pushed to have construction fees scrapped or cut, and after talks with the mayor, the fees came down.

He fired off complaint after complaint to the interior ministry and to prime ministers, and his public attacks reached political leaders in Sofia too. In an open letter, he called Plovdiv a "feudal city" and accused businessman Ivan Petleshkov, a former boss of football club Lokomotiv Plovdiv.

PIMK is the biggest transport company in the Balkans, with branches in Italy that it uses to run freight across Europe.

Filipov also owned Bulgaria's only private rail terminal, near Plovdiv. He used it to send goods to Asia on his own trains and wanted to carry passengers too. He had his eye on a concession for passenger services on private lines that the state was planning to hand out.

His construction firm has projects in Sofia and worked on the Hristo Botev stadium. Work there was halted and restarted several times, amid rows with the city council and national authorities, with the state repeatedly asked for extra money as funds kept running short. The stadium has swallowed 50 million levs in state funding.

Filipov's name last made headlines in March last year, when he was questioned as a witness in the case against the "Naglite" ("The Insolent Ones") crime group. His company was also checked at the time over suspected cocaine shipments by truck to Turkey, but nothing was found.

Over the years his name has also come up in transport industry protests over road tolls and fuel prices, including road blockades.