An arrest warrant was issued on Tuesday for a 41-year-old German man accused of assaulting several dentists at their clinics in Nakhon Ratchasima and damaging their equipment over a period of three-and-a-half months.

The provincial court approved an arrest warrant for the man, identified only as Heffner, on three charges - trespassing, assault and damaging property.

Local and immigration police went to the man's house in Non Sung district, only to find that the suspect had fled in a pickup.

The man was driving a dark green Ford Ranger, and police were looking for him.

The approval of the arrest warrant came after questions were raised over police inaction in the case after multiple complaints from dentists that they had been assaulted by the man.

A woman dentist first filed a complaint against the man with police on Nov 30. She said she was physically attacked by the German after he punched through a door to get into her dental clinic room. 

Several other assault complaints have since been lodged against the man by other dentists, who also accused him of damaging their equipment. 

The most recent attack was reported on Friday last week. 

The man's Thai wife said that he suffered from a mental illness but did not receive treatment, a source said.