The incident happened around 8:30 pm last Tuesday night.
The man entered the café, left his bag and went out again. After the explosion he returned for his bag.
Police identified the man as being of 'southern heritage' and in his thirties.
He stood 1.90m tall and, apart from that, had a normal build.
He was unshaven, was probably wearing a light-coloured false beard, a black coat, a cap and black gloves.
Flandersnews.be / Expatica