Ertzaintza police officers keep watch over the martial arts premises in Bilbao where human remains have been found. Alfredo Aldai / EFE

Police officers in Bilbao have arrested a world champion kung fu martial artist on suspicion of murder after being alerted to a violent assault on a prostitute by members of the public.

When agents of the regional Ertzaintza police force arrived at the Zen4 gymnasium owned by Juan Carlos Aguilar on Sunday night, they found the prostitute badly beaten on the floor. Officers also uncovered human remains in garbage bags in the building and launched a search of the surrounding area.

Divers were also called in to trawl the city’s river in the Duesto neighborhood. Aguilar confessed to the murder of a prostitute of Czech origin after being taken into custody and further human remains were found at his home by police search teams.

“It took us longer to get in than we would have liked,” said Ertzaintza police chief Lucio Cobos. Officers were forced to smash down the gate protecting the gymnasium. The authorities believe that Aguilar, who was standing over the battered woman and did not resist arrest, acted alone.

Cobos told reporters that forensic investigators were trying to determine if the remains pertained to one or more cadavers. His intended victim was taken to hospital in a serious state and is in a coma.

Aguilar was crowned world kung fu champion three times and national champion on eight occasions. A well-known figure in the martial arts world, he won fame after reportedly becoming the first Westerner to be titled a Shaolin master in China.

“There is a large deployment in various areas of Bilbao,” said Cobos, as the search for further potential victims continued. The main refuse tip in the city was also being combed for garbage bags originating from the central area of the city. Cobos added they would be gone through “one by one” as part of an investigation he said would take “a very long time.”

Aguilar because famous in the late 1990s after qualifying as a Shaolin master and was interviewed extensively by newspapers, television and radio. He appeared in internet clips performing kung fu moves in the orange robes of a Shaolin monk at the eponymous temple. In one interview with TVE, Aguilar described martial arts as a path to “controlling your emotions.”

In a 2007 interview with Antena 3 television station, Aguilar said: “As a Buddhist, I believe that souls are human beings. I communicate with them. I ask them for permission and I ask them for forgiveness.” Investigators are trying to determine whether Aguilar was receiving treatment for psychological disorders, Cobos confirmed.